What is an Ace, a #1, or a #3 Starter? How Good Are St. Louis' Starters? And How Important Is It?

Photo by Scott Rovak/MLB Photos via Getty Images

Editor's note: Hey everyone! We here at Viva El Birdos are very lucky to have a long history of having a passionate and intelligent community, so something I want to try to do is start promoting more Fanposts! Here is one that appears to have been painstakingly and lovely crafted by CaliforniaCanadian about the Cardinals starters and the importance of top of the rotation starters in the playoffs that I thought you all would enjoy. Happy Friday!

In preparation for Opening Day* and the start of the 2023 season, I wrote this, my second fanpost, which was inspired by the seemingly never-ending discussions in the comment sections about how good are the Cardinals' starting pitchers, whether or not it is critical to have an ace or TOR pitcher in the post-season, exactly what is a TOR or average pitcher, and do they Cardinals have one? I wanted to take a look at recent history to see if I could develop some quantitative answers to these questions knowing well that it may just lead to more questions and discussion (aka friendly argument). This post is longer than I expected (both in time and words) so here is an outline of the article in case you want to jump ahead.

1) Methodology for the article

2) Pitcher results by Tier

3) Impact of TOR in the Playoffs

4) How about the Cardinals?

* If Opening Day is any indication we are in for a wild and exciting season, though hopefully with fewer heartbreak moments. The good thing is that one game doesn't define a pitching staff.

1A) How to Measure This

To make this a quantitative argument I needed to determine how to measure the effectiveness of starting pitchers. To come up with an objective rank order of pitchers using one metric that encapsulated the value a starting pitcher provides would be ideal. There are two specific questions I am looking to answer.

1) What is the performance level of the ‘tiers' of starting pitchers, i.e., Ace, #1, #2, #3, etc.?

2) How much does a TOR pitcher (Ace or #1) add to the chance of winning a playoff game or series?

For the purposes of my evaluation, I chose to measure pitchers based upon the WAR they earned per game started (WAR/GS). This addresses both questions fairly well. Over the course of a season (~30 starts) this will give us an idea of how various pitchers rank in their contribution to their team winning games and making the playoffs, while not penalizing players who don't start the whole season. And during the playoffs pitchers who had the highest WAR/GS would be those who had the best chance of helping their team win a playoff game.

1B) Methodology

I went with the Fangraphs' version of WAR because Fangraphs provides a simple split of pitcher statistics between starting and relieving games, i.e., I could easily look at WAR per game started. This is less than ideal though because there are differences between fWAR and bWAR that might undervalue some pitchers due to the fact that fWAR is based upon FIP (projected results). What I found though is that Fangraphs also has a breakdown of fWAR that includes a Runs Allowed WAR (which I'll call raWAR) that more closely tracks bWAR, though not precisely. For purposes of this study, I chose to average fWAR and raWAR to get a metric (aWAR) that reflects both actual performance and a projection of future performance. Here are the steps I went through to get the pitcher rankings.

  1. Download all starting pitcher data from 2018-19 and 2021-22. I excluded 2020 due to the short and odd nature of the season. This gives me 1,474 pitcher seasons or about 12 per team per year.
  2. Calculate aWAR/GS for each starting pitcher for each season.
  3. Segregate any pitcher with less than 10 starts (or who was an ‘opener') into an ‘Other' category. I wasn't comfortable assuming that aWAR/GS was stable at these smaller sample sizes. My cutoff of 10 is somewhat arbitrary but did result in a reasonable subset. This Other group included 747 pitcher-seasons or about 6 per team per year.
  4. Rank the remaining pitcher seasons by aWAR/GS and segregate them into tiers of 120 (one per team per year = 120). Essentially if pitching value was evenly spread across the league each team would have one pitcher a year in each tier. The end result was 5 tiers of 120 pitchers and a 6th tier which had 127 pitchers in it. Thus, on average each team had 6 pitchers a year that had 10 or more starts which fits the anecdotal evidence.

2A) Pitching Tier Results

The segregation of pitchers into tiers based upon aWAR/GS also delivers us information on the underlying components that lead to this performance and the results also reflect a gradual hierarchy of these underlying ‘skills' as might be expected. The first table below shows the raw data results of pitchers across the 7 tiers. The key result is the steady increase in aWAR/GS (our metric) with the largest jump coming for the #1 (TOR) pitchers. This demonstrates that even the top 30 pitchers in a year typically have a significantly higher value than #2-6 starters, in fact it is 70% higher than a #2 and more than 2x a #3.

Starting Pitcher Tiers

The second table provides some more familiar rate stats which reinforce the value of a #1. The average WAR for a #1 is almost 5, with a #2 just below 3 WAR, and a #3 is slightly below 2 WAR. It goes down from there with both #6 and ‘Other' starters being below replacement level. These latter pitchers, as a group, started almost 25% of games and threw 20% of innings from starters so this is not insignificant. This demonstrates the value of having depth beyond the #5 starter for when the almost inevitable injury occurs. There are a couple of other takeaways from this table:

  1. IP/GS also goes up with the quality of the pitchers, rising from 5 for #5 and #6 starters to 6 for #1s.
  2. Not surprisingly the number of games started goes up for the best pitchers.
  3. More interesting is that the better the pitcher the more likely he is to have an ERA better than his xFIP. This does support the notion that pitchers with better stuff (those with better overall results) can control more than just K%, BB% and HR%. We'll see more on that later.

Starting Pitcher Values

Overall, we see that an average pitcher, i.e., a #3 starter, provides less than 2 WAR per year, starts 24 games with an ERA of right around 4. Meanwhile a #1 starter will provide almost 5 WAR in a year with 27 starts and an ERA of less than 3. At the other extreme, an average #5 starter is barely above replacement (0.5 WAR), only starts 20 games, and has an ERA of almost 5.

2B) Pitcher vs. Batter Level Results

What drives the better results of the top pitchers? What you will see next are averages across each tier so an individual pitcher's results will vary from these, but the progression of the cumulative results from individual at bats is informative.

In the first table you will see that each of the lower level metrics shows a distinct trend of improving performance as we go up the starting pitcher tiers. This is not surprising, but the uniformity of the improvement was a little surprising. #1 starting pitchers are better, on average, than a #2 at everything from K%, BB%, Strike%, WHIP, BABIP, LOB%, and HR/9. Individual pitchers though might excel by being great at one or two things while being below average at other things (think Nolan Ryan).

Starting Pitcher Rate Stats

The table below dives deeper into how each at bat ends if the ball is hit. Here the trends are less dramatic, but still show definitive improvement. Better pitchers give up fewer line drives, less barrels, lower exit velocity, and fewer hard-hit balls. They also induce more ground balls and fewer fly balls to pair with a lower HR/FB%. This reinforces the theory that pitchers can influence batted ball results to some degree, particularly if pitchers are able to replicate these results from year to year.

Starting Pitcher Batted Ball Stats

2C) Who are the TOR pitchers?

There were 78 different players who achieved a rating of #1 in one season or more over the past four years. The #1 tier was defined to include ~30 pitchers per year or 120 seasons so the average TOR pitcher appeared on the list one and a half times. There were a few pitchers though that were consistently on the list, but just a few. Three pitchers accomplished #1 ranking in 2018, 2019, 2021, and 2022. They were Max Scherzer, Jacob DeGrom and Clayton Kershaw. Another six made it in three of the four years. Brandon Woodruff, who had just 4 starts in 2018, Gerrit Cole, who slipped to a #2 in 2022, Justin Verlander, who missed 2021 completely, Shane Bieber (who some dream on), who started as a #2 in 2018 at age 23, Walker Buehler (missed chance #1), though he slipped to a #3 last year, and Zack Wheeler, a high #2 in 2019. And there's an up-and-coming group of nine pitchers who made it the last two years running. Some familiar names populate that list: Carlos Rodon, Julio Urias, Patrick Sandoval, Kevin Gausman, Corbin Burnes, Sandy Alcantara (miss #2), Logan Webb, Shohei Ohtani, and Max Fried. Thus there were just 18 pitchers who could have been considered consistent TOR pitchers over the past two years. Looking ahead there were 14 pitchers who made it on the list for the first time last year. Based upon history though we should only expect 5 (~35%) of them to repeat as a #1 this year.

TOR Pitchers

Who are the best of the best though? The undisputed Aces? Are they the pitchers that consistently reach the top tier? Or are they the ones who deliver the very most WAR per start? In an attempt to assess who the aces were each year I looked for pitchers who delivered at the rate of 5 WAR per 30 games started or more. This is the type of pitcher we all want starting a playoff game or two. It turns out that there were just 54 pitcher-seasons at this level over the four-year period. That's 13 to 14 a year or about half of the #1 starters, i.e., la crème de la crème. It turns out to be a little harder to be a consistent ace, but there are some pitchers (the usual suspects) who do it. The two four-time Aces are Max Scherzer (miss #3) and Jacob DeGrom. The three-time Aces are Gerrit Cole and Justin Verlander. Two-time winners include Carlos Rondon and Zack Wheeler in 2021 and 2022, and Walker Buehler, Aaron Nola, Tyler Glasnow, and Lance Lynn (miss #4)! There are 28 one-time Aces with 7 from last year including Sandy Alcantara and Zac Gallen (miss #5).

3) What is the Value of a TOR Pitcher in the Playoffs?

It is likely that the Cardinals will make the playoffs even with an average rotation. The question that comes up in our online discussions is whether or not this is good enough for the playoffs. I'd like to examine recent history in a couple of ways to see how well teams have fared depending upon how good their starting pitchers were. This is not an exhaustive study, and the small sample size might render the conclusions meaningless, but it is a place to start. Here we go.

Study 1 - Theoretical Value of an #1 SP

Let's start with a theoretical calculation of the improvement a TOR starter can provide to the odds of winning a single game. Assuming two teams equal in all ways (~95 wins), if we play a game in which one team has a #1 starter and the other has a #3 starter, then the second team will score about 0.3 runs less on average. This is based upon the runs allowed per game differential between a #1 and a #3 plus a #4 reliever to cover the extra outs needed in the sixth inning and assuming pitching determines 40% of the amount of runs scored (my wild guess). That converts to an increased chance of winning of ~4%, that is 54% vs. the initial 50% (since the teams were equal). Thus a TOR starter slightly increases the odds of a team winning as compared to a #3, but it is far from a guaranteed win. Does this hold up in real games?

Study 2 - Playoff Games Winners

To see if this winning edge holds up in real games I went through the last four years of playoff games, again excluding 2020. Over 147 games I compared the starting pitchers and determined the outcome on which team won the game. Obviously the two teams playing in any of these games are not equal, so the pitchers' values are not the only factor in determining the winners. How well did teams with a #1 starter in the game fare? Coincidentally, they won 54% of their games. Can we do better though? Looking at just games started by Aces, the winning percentage rises to 58%. However, this is on par for the winning percentage of any game when the starting pitcher is just better than his opponent (as graded by the Tier system, e.g., a #2 vs. a #3) which is 57%. What about other factors? The team with the better season W/L record won 56% of their playoff games and home teams won 55% of the games. So, while starting a TOR (#1 or Ace) in a playoff game improves a team's chances of winning said game, so does playing at home, having the better pitcher, and being the better team at about equal rates.

Playoff Game Winners

How do other pitchers do during the playoffs? The following table shows that most pitchers have a better than 50% winning % against lower tier pitchers and a losing record against better pitchers, but the overall edge is just 7%. This is another point demonstrating that a good pitcher can provide a small, but real benefit towards winning a playoff game, though there other factors as well (team record, home or away, other team's pitcher) along with a random factor that may be larger still. How well do teams do though that have a rotation of strong pitchers? Are they more likely to win the World Series? We'll look at that next.

Pitcher Playoff Records

Study 3 - Playoff Teams

Do teams that advance further in the playoffs have TOR pitchers? A belief espoused by some is that a team needs a TOR pitcher to advance in the playoffs. I examined the past 20 years to see if each playoff team's rotation had a TOR pitcher (using 2018-22 standards). In this case it does appear that having a TOR pitcher or more does improve the odds of a team advancing in the playoffs. The table below shows the average number of TOR starters (Aces and other #1s) as teams advance and we see an increasing number of such pitchers. Wild-card losers tend to have only 1 TOR starter, while teams that make it to the World Series have 2.3 TOR pitchers on average. In this case, the aggregation of TOR starters does seem to improve a team's chance of advancing.

Playoff Progression

Study 4 - World Series Teams

Focusing solely on teams that make it to the World Series, what can we learn about their rotations? Several things, though none may be predictive. The team in the World Series with the better rotation (top 4 starters measured by aWAR/GS) only won 6 out of 19 World Series (one series had essentially equal staffs) and that trend doesn't seem to be reversing (1 out of the last 4).

How good are the rotations that make it to the World Series? Let's look at these using the aWAR/30 for each team's top 4 starters. (Remember that an Ace averages 6 WAR/30, other #1s = 4.5, #2s = 3.2, #3s = 2.4, and #4s = 1.7.) World Series teams definitely have better than average rotations, which is expected since they are better than average teams. The majority of these teams (28 out of 40) had rotations with aWAR/30 between 3 and 5. Ten percent had Ace level rotations averaging over 5 aWAR/30. Seven had above average (2 to 3 aWAR/30) rotations and only 1 had a rotation below average (1.8). So having multiple good starters helps a team get to the World Series, however it is not the predominant factor in winning a World Series as shown below. The winning percentage doesn't increase with the better staffs, rather it fluctuates between 40% and 60%.

World Series Winners

One thing to note is that the World Series rotations seem to be getting better in recent years. It doesn't appear to be the result of great pitchers being traded mid-year, but perhaps it is a result of the ‘super-teams' idea. In any case over the first 10 years I studied (2002-2011) the aWAR/30 for World Series rotations was 3.5. It was the same over the next 5 years, however over the last 5 years (encompassing 2017-2022) it was 4.4. This is more than one standard deviation above the average and there's a less than 1% change that this happened by chance. Houston was four out of the ten teams in this period though so their rise to almost yearly appearance in the World Series is a factor as well.

Just for fun, here are some of the best and worst of World Series rotations over the past 20 years.

Just for Fun

So, can we conclude that TOR pitchers are necessary for playoff success? Having better pitchers, especially TOR pitchers, does contribute to winning a higher percentage of individual games. Having more TOR pitchers does lead to going deeper in the playoffs. But neither are guarantees and the increase in winning doesn't seem to exceed 10%, leaving an individual series still subject to random factors as evidenced by the poor record of stronger staffs in the World Series.

4A) How Do the Cardinal Starters Stack Up?

Ignoring the five TOR pitchers that the Cardinals missed their chance with, how do the remaining pitchers rate on the WAR/GS scale? The results, as you might have suspected, are that the Cardinals' rotations over the past four years have been very average, i.e., few highs, few lows, and a crowd in the middle. Looking at the table below the Cardinals have fewer #1s, #2s, #4s, #5s, and #6s, than the average of 1 per year, but twice as many #3s. It almost seems like the Cardinals are risk averse and play for safety when finding their pitchers.

Cardinal SP Tiers

So how did individual pitchers fare? Here's the list of Cardinal starters over the years and their tier ranking. It turns out that the Cardinals have had three different #1 pitchers, missing only in 2022. Miles Mikolas, Jack Flaherty, and Adam Wainwright reached this level in 2018, 2019, and 2021 respectively. These three also turned in the three seasons of #2 pitching and along with a #3 season each, and one ‘missing' (Other) season each of less than 10 starts. Fairly consistent output, though a little below average, and certainly not predictable as to which pitcher would deliver the goods.

Cardinal Starters

4B) Projections for Cardinal Starters

What do the projections show for the Cardinal starters in 2023? My metric, aWAR/GS, is less dependent upon health and games started since it is a rate stat. Unfortunately, it is also harder to tease out of the projections since a large number of the Cardinal pitchers have projections that combine starting and relieving. I did my best to estimate the aWAR/GS, but there is definitely a greater error band in these figures. Nonetheless it is still instructive and interesting to see what the projections show. I used ZiPS since it was readily available and has been one of the more accurate projection systems. It also includes 80% and 20% projections along with the mean so we can see the possible good and bad.

So, what do we get this year? Not surprisingly much the same as we had in prior years. ZiPS projects the Cardinals to have two #2s, three #3s, and a #4 in their starting rotation (counting both Wainwright and Woodford since most teams average six starts with more than 10 starts in a year). Waiting in the wings are two #3s and a #4. Can you guess who is who? On the positive side, two of the pitchers have #1 (but not Ace) upside at 80% and six(!) have #2 upside. Thus, there is a way for the Cardinals to have a very good rotation without a trade, even if it is unlikely. On the downside we could end up with nothing but #4 and #5 starters if all underperform to their 20% projections (excluding a low #3 rating for Jordan Montgomery). Here are the projections for the starters and backup starters. The aWAR/GS is my estimate, the aWAR/30 just normalizes this over a ‘full' season of starting, the Tier is based upon the aWAR/GS performance levels of 2018-22, and the Quintile just shows where in the Tier the pitcher lands with 1st being the best in a Tier and 5th the lowest.

Cardinal SP Projections

It is interesting to look at the component projections for the pitchers to see how they arrive at their results. ZiPS provides projections for BB%, K%, BABIP, ERA-, and FIP that we can compare to pitchers across the prior 4 years. Here are some general observations that match expectations.

1) Cardinal pitchers have good BB% rates with 4 of their top 6 starts showing similar rates as #1 and #2 pitchers.

2) Their K% rates though are mixed with a couple of above average pitchers, but most of them below average.

3) Cardinal starters are projected to have very good BABIP numbers, likely a result of the defense behind them. The one anomaly is Steve Matz, who has a high BABIP in the range of a #5 starter. If this turns out not to be the case, then he could easily exceed his projection as a #3 starter.

4) The ERA projections are slightly better than the FIP projections, which make sense given the defense's impact on ERA.

Cardinal Rate Projections

Let's take a look at the individual Cardinal starters in more detail, with a look at the aWAR/GS for each pitcher along with the rate stats that underlie those results. We'll look at the past four full years and the ZiPS projections for 2023.

Jordan Montgomery

Jordan Montgomery is projected by ZiPS to be the best Cardinals starter, safely in the #2 SP tier with the upside of a #1. His mean projection is based upon rate stats that are just slightly worse than his results for the full year in 2022 so it would seem reasonable to expect that he could exceed the mean projection. Unfortunately I don't have the rate stats that deliver the 80% results, but an improvement in his K% rate to his 2021 levels would be a significant improvement. An improvement in BABIP would help, though his BABIP with St. Louis was .287 which matches the projection for this year.

Jordan Montgomery

Jack Flaherty

As many have noted, the uncertainty around what Jack will achieve in 2023 is great, due to his injury history and the impact it has had on his results in the past. ZiPS projects him to be a borderline #2 starter with upside to a #1, but downside to a #4. ZiPS sees him achieving better rate stats than last year across the board so the risk is apparent. Still, the projections are significantly lower than his results in his Ace year of 2019, hence the upside which we've seen before.

Jack Flaherty

Miles Mikolas

Father Time is making his appearance in the ZiPS projections for Miles as each rate stat gets slightly worse resulting in him being a high #3 starter as compared to a #2 last year. He still has that upside and just needs to maintain what he did last year to achieve that. Most critical is keeping a low walk rate and home run rate since he is unlikely to strike out a high percentage of batters.

Miles Mikolas

Steven Matz

Matz is the pitcher I expect to show the biggest gains from last year and to surprise people. His mean projection is for a low #3, but the rate stats are a mixed bag. The projected BB% and K% rates are in line with his career rates, but much worse than they were in his 10 starts with St. Louis. On the other had his projections for BABIP, HR/9, ERA and FIP are better than last year and more similar again to his career rates. If he can maintain the BB% and K% rates from last year, and improve on the bad luck he had with BABIP and HR/9, then he could end up as a #2 starter.

Steven Matz

Adam Wainwright

Adam is just two years removed from being a #1 starter, but last year was a drop-off from that level mainly due to a lower K% rate and a higher BABIP. The higher BABIP should not have been surprising because his 2021 rate was his career low (full season) and 2023 is just slightly higher than his career average. The projections look reasonable, and I would be happy to have him end his career as a #3 starter.

Adam Wainwright

Jake Woodford

There's little starter history for me to test the projections against, but they look like a reasonable base level for Jake. If his Stuff improvements are real, then it seems like he could easily perform a tier above the #4 starter he is projected as.

Jake Woodford

Matthew Liberatore

Liberatore's projections are surprisingly positive given his short history of MLB results. The rate stats line up with those of Jordan Montgomery albeit with a slightly higher walk rate. If this is what he delivers as a 23-year-old pitcher it would bode well for his continued development.

Matthew Liberatore

Connor Thomas

Adam 2.0? His projections line up with Wainwright's for 2023 so this isn't the Ace version of Adam, but this is also better than most of us would have projected just a year ago. He obviously gets there in a different way, but the value could be the same. It will be interesting if we get the chance to see if his results can live up to this.

Connor Thomas

Dakota Hudson

And last, the enigmatic Dakota Hudson. I almost left him off of this list, but there is a chance we will see him start games for St. Louis. ZiPS is projecting improvements from his 2022 season in most areas with the result being a season similar to his 2019 season which was just #4 starter level, though it is hard to see that right now.

Dakota Hudson

Conclusion (TL;DR)

The Cardinals' rotation has the same construction as prior years, namely a higher-than-average number of solid, but not spectacular starting pitchers. This serves them well during the regular season when combined with an offense and a defense in the upper tiers as reflected in their consistent finishes in the high 80s to low 90s wins, but it has let them down in recent playoffs. However even the Cardinals' teams that reached the World Series (and won 2 out of 4 series) did not have great pitching (the 2013 team, the best, was 25th out of the last 40 teams to make it to the World Series) so it is possible to succeed without great pitching. That said, having a TOR pitcher increases the odds of winning a single playoff game slightly (~4-8%) and having multiple TOR pitchers helps in going deeper through the playoffs. It is possible that one or two or even three pitchers in the current staff could improve to reach the TOR level in 2022, but if this doesn't happen, then I believe a trading deadline deal for a TOR could make sense depending upon the price. I don't think dealing for a mid-range pitcher like Quintana or Montgomery would help as much since the Cardinals already have a queue of similar pitchers waiting to come up and a team usually only uses 3 or 4 starters in the playoffs.