clock menu more-arrow no yes mobile

Filed under:

Finding a Jack Flaherty Comp

Which historical pitchers are most similar to the emergent ace?

Pittsburgh Pirates v St Louis Cardinals Photo by Dilip Vishwanat/Getty Images

Jack Flaherty just completed a tremendous sophomore season. He finished fourth in National League Cy Young voting on the strength of a 2.75 ERA, 4.7 fWAR, 80 FIP-, and absurd 0.91 second half ERA. He established himself as the star that the Cardinals’ deep roster has so desperately needed in recent years. This is all in addition to an impressive rookie campaign in 2018. He conveniently turned 24 on the exact day the season ended, meaning he tidily has two complete seasons (and some light change from 2017) through his age 23 season. It’s a nice cut-off for us to find some historical comps for what he has accomplished in his career to date.

We’ll start with the following parameters:

  • Right-handed pitchers
  • Through age 23
  • +/- 100 innings pitched of Flaherty’s 368.2
  • Two eras- since integration in 1947, and since 2002

I could overthink this and zero in on categories that make Flaherty unique, much like last year’s list of Harrison Bader comps that focused on defense and baserunning. However, pitcher comps are best when we simply use the FIP categories. We’ll use K%, BB%, and HR/9. FanGraphs has made this much easier over the last year, adding plus stats that compare players to their peers. Those three categories will be league-relative. After all, Nolan Ryan’s 23.4% K rate through 1970 is not the same as Joba Chamberlain’s 23.4% through 2008. The plus stats will account for that.

We can also include league-relative batting average against (AVG+), even though it’s imperfect for many reasons. Defense and raw luck diminish the value of the metric, but including AVG+ gives us a general idea of how hard it was to get hits against a pitcher. We can dampen its effect a bit by weighting it lower in our formula.

Finally, you may have noticed that I listed two eras. The broader era allows us to cast a wider net. However, batted ball data (LD, FB, and GB%+) is unavailable before 2002. We’ll include that info for the second group, and obviously exclude it for the larger group. I’ve weighted K%, BB%, and HR/9 at five times the importance of batted ball types and AVG+. Here is our baseline- Jack Flaherty’s plus stats:

Jack Flaherty, Plus Stats

Name K%+ BB%+ HR/9+ AVG+ LD%+ GB%+ FB%+
Name K%+ BB%+ HR/9+ AVG+ LD%+ GB%+ FB%+
Jack Flaherty 128 97 97 81 101 94 107

For each pitcher, I calculated the raw difference from Flaherty in these categories and plugged it into the formula to find the weighted difference. It’s important to note that this type of thing isn’t predictive. The game is changing at breakneck speed, with unexpected players elevating their production to heights rarely seen in the past. It wreaks havoc on projection systems. In short, these lists are fun, but they’re only good at wishcasting Flaherty’s future.

Here are Flaherty’s ten closest comps going back to 1947:

Flaherty Comps since 1947

Name HR/9+ K%+ BB%+ AVG+ Weighted Diff.
Name HR/9+ K%+ BB%+ AVG+ Weighted Diff.
Jake Peavy 106 125 98 94 4.88
Bob Welch 93 121 99 94 4.88
Luis Severino 92 123 90 90 5.88
Mat Latos 88 123 91 89 6.75
Ramon Martinez 103 131 86 89 6.75
Scott Sanderson 111 128 87 95 8.38
Billy Loes 107 114 96 95 8.69
Lance McCullers 95 128 122 88 8.88
Art Mahaffey 110 117 95 94 8.94
Steve Busby 78 128 107 101 10.31

This is an interesting group if you love baseball history. It puts the performance of some of these pitchers in perspective. If you didn’t realize how good Bob Welch, Ramon Martinez, Jake Peavy, Scott Sanderson, or Steve Busby were when they were young, now you know they were the Jack Flaherties of their respective eras. McCullers (senior here, not junior) is an odd fit because he was almost exclusively a reliever.

The most pertinent names are the closest- Peavy and Welch- and it just so happens that both of them won a Cy Young award. For that matter, Luis Severino finished third in Cy Young voting at one point, Mat Latos finished eighth, and Martinez had second and fifth place finishes. Every pitcher in Flaherty’s top 10 made an All-Star team except McCullers and Latos.

Now let’s introduce batted balls and find comps since 2002. Given the list above, you can probably guess a few inclusions. Here are Flaherty’s closest comps since 2002:

Flaherty Comps Since 2002

Name K%+ BB%+ HR/9+ AVG+ LD%+ GB%+ FB%+ Weighted Diff
Name K%+ BB%+ HR/9+ AVG+ LD%+ GB%+ FB%+ Weighted Diff
Jake Peavy 125 98 106 94 98 94 109 4.37
Mat Latos 123 91 88 89 83 96 114 7.11
Luis Severino 123 90 92 90 99 113 85 7.21
Yovani Gallardo 134 115 89 88 107 96 101 9.53
Michael Wacha 104 97 82 92 101 96 105 11.05
Ervin Santana 103 102 92 93 90 86 122 11.63
Joba Chamberlain 135 115 79 94 101 106 93 13.37
Josh Beckett 145 109 79 90 91 97 110 13.68
German Marquez 110 80 105 104 108 105 88 14.47
Joel Pineiro 104 87 82 92 93 110 93 15.47

The top of the list- Peavy, Latos, and Severino- certainly isn’t surprising, though it’s notable that the inclusion of batted balls pushes Latos just barely closer than Severino to Flaherty. The batted ball data for the young version of Michael Wacha is a key component to his appearance at fifth on this list, with his batted ball tendencies almost exactly in line with Flaherty’s. The same is true of Yovani Gallardo to a lesser degree. His batted ball similarity to Flaherty overcomes their large difference in walk rates.

It’s easy to forget that Joba Chamberlain was a starter early in his career, although there are some massive differences between him and Flaherty. Ervin Santana is reasonably close in most categories, but there are sizable gaps in K% and FB%. If I had used K/BB+ instead of breaking them out individually, Josh Beckett and German Marquez would both place higher on the list. Their ratios relative to league are almost identical to Flaherty. Breaking the metrics in two keeps them towards the bottom. Believe it or not, Joel Pineiro was a highly effective starter early in his career (4.4 fWAR in 289 IP through age 23), but his appearance here seems more a formality based on the limited number of pitchers who get past our initial parameters. You could say the same for everyone on this list past the first three, and possibly Wacha since Flaherty is pitching under the same organizational philosophy.

San Diego Padres v St. Louis Cardinals Photo by Elsa/Getty Images

We can add all of the caveats we want, but the most obvious comp by far is Peavy. Their batted ball profiles, strikeout rates, and walk rates are all eerily similar. Every one of those categories has a difference of 3 or less. Where it gets really fun is where they’re different. Flaherty has yielded a lower average against and a lower homerun rate than young Peavy. Mind you, the difference in batting average against is surely because of the elite defense Flaherty enjoyed behind him in 2019. The Padres of Peavy’s youth were an average to slightly worse defensive team. That still leaves homerun rates. As much as Busch III plays as a pitcher’s park, it’s not quite as extreme at homerun suppression as Petco Park. In other words, Flaherty is pitching in a park that yields more homeruns than young Peavy did, and is still allowing fewer of them.

That’s where we end up on this journey. Which pitchers are the most comparable to Jack Flaherty? Imagine Jake Peavy early in his career, the Peavy that led the league in ERA in 2004 in all of his nicotine stain yellow uniformed Padres glory, but eliminate some homeruns allowed. That’s quite a starting place for the rest of Flaherty’s career.