Evaluating Oli Marmol’s Pinch Hitting Decisions

We’re now into the second season of Oli Marmol’s tenure as manager of the St. Louis Cardinals, and one thing is clear - he likes to pinch hit more than his predecessor.

Last year, the Cardinals had the 8th most plate appearances by pinch hitters. That’s comfortably in the top third of the league even if it’s not an excessive amount but that’s a marked uptick from Mike Shildt’s tenure.

In Shildt’s 3 full seasons of management, the Cardinals ranked 11th in 2019, 18th in 2020, and 15th in 2021, putting the team right around the middle of the pack in terms of pinch hitting.

It’s clear that Marmol has been more aggressive with the use of his bench in an effort to gain the platoon advantage as often as possible, but the question I want to ask is...has he been too aggressive?

To evaluate that, I’ll start by establishing a facts, using them to create a few pinch hitting rules, and then using those rules to evaluate all 7 pinch hitting decisions made by the manager in 2023.

Fact #1 - Pinch hitters lose, on average, 34 points of wOBA

This number comes straight from the research Tom Tango conducted when he wrote The Book, which is a fantastic read if you like numbers and baseball.

For those of you who read my articles, you’ll know that I reference wRC+ a lot and wOBA very little. That’s because wRC+ is easy and helpful. The + makes it easy to know whether a hitter is good or bad. Or great as opposed to just good. Or average as opposed to above or below average.

That’s because wRC+ is scaled so that 100 is average and every point above or below 100 is one percentage point above or below average. So a hitter with a 120 wRC+ is 20% above average, while a hitter with an 80 wRC+ is 20% below average. How easy!

wOBA isn’t as easy even since it isn’t scaled the same way as wRC+. But to know whether a wOBA is good or bad, you just have to know what a good OBP is and a bad OBP is as wOBA is generally on the same scale as OBP.

So, using that knowledge to evaluate the impact of fact #1, you’ll understand just how significant it is to lose 34 points of wOBA. Think about a hitter losing 34 points of OBP. A .334 OBP hitter is pretty good. Above average even. But a .300 OBP hitter is one who will likely never sniff the top of the lineup.

A 34 point difference in wOBA is the difference between having 2022 Lars Nootbaar at the plate versus having 2022 Tommy Edman at the plate. Or to make the significance even clearer, it’s roughly the difference between having 2022 Dylan Carlson at the plate instead of 2022 Andrew Knizner.

That’s big.

So, it shouldn’t take much explaining for you to figure out why this is important. Think about it this way. If Oli Marmol wanted to pinch hit with Dylan Carlson last year, he could roughly expect to receive Andrew Knizner-level production.

There’s obviously more that goes into a decision to pinch hit or not but that’s definitely something to weigh when making that decision.

Why does this happen? It’s hard to say for sure, but it’s easy to hypothesize. Baseball is a game about rhythm and timing. What kind of rhythm does someone have when he’s been sitting on the bench for the last 2 hours? The answer is not much.

It’s the same reason why we often say that it’s hard for a bench player to put up good numbers. When playing time is inconsistent, it’s hard to establish (and stay in) a rhythm.

Morale of the story - pinch hitting is hard.

Fact #2 - When facing a LHP, the difference between a left-handed and a right-handed hitter was 32 points of wOBA in 2022

If pinch hitting didn’t make sense after fact #1, hopefully it makes more sense now. There’s a big wOBA penalty for pinch hitters but there’s also a big penalty for lefty hitters facing lefty pitchers.

If 32 points of wOBA seems like a lot, I should point out that there was a 40 point difference in 2021 and a 34 point difference in 2020. The difference was only 23 points in 2019, but you get the point - The pitcher has a big advantage in lefty-on-lefty matchups.

This works both ways, though. The right- handed hitter has a big advantage when he steps into the box against a lefty.

Fact #3 - When facing a RHP, the difference between a right-handed hitter and a left-handed hitter was 3 points of wOBA in 2022

This is interesting. There’s a huge difference between a left-handed hitter and a right-handed hitter when a lefty is on the mound but there really isn’t much of a difference when a righty is on the mound.

The difference was 12 points in 2021, -3 points in 2020 (meaning that righty hitters actually fared better than lefty hitters when a right-hander was on the mound), and 16 points in 2019. 2020 was weird but it feels safe to say that the platoon advantage here is worth about 10-15 points of wOBA.

Suffice it to say, the platoon advantage with a right-hander on the mound is important but not nearly as important as the platoon advantage when a lefty is on the mound.

Rule #1 - Pinch hitting without gaining the platoon advantage is almost never worth it

This rule is simple. There’s a 34 point wOBA penalty for pinch hitting, so, without gaining the platoon advantage, the pinch hitter would need to be at least 34 points of wOBA better than the hitter he is replacing for the move to make sense.

This is a scenario that won’t happen often as any hitter who is good enough to make up that 34 point gap is likely a starter already. Still, it’s possible to imagine a scenario in which Paul Goldschmidt or Nolan Arenado have the day off and could be pressed into duty late in the game to pinch hit for someone like Andrew Knizner.

I wanted to start with this rule because the next 2 will operate on the assumption that pinch hitting will gain the platoon advantage.

Rule #2 - When pinch hitting to gain the platoon advantage against left-handed pitchers, the pinch hitter must be at least as good as the hitter he is replacing, and ideally better, for the move to have a positive effect on run expectancy

After reading fact #2 and fact #3, this should make perfect sense. A left-handed hitter facing a left-handed pitcher is the worst matchup in baseball from a hitting perspective while the best matchup in baseball from a hitting perspective is a right-handed hitter against a left-handed pitcher.

Against left-handed pitching, it’s okay to be aggressive with pinch hitters because the 34 point pinch hitting wOBA penalty is practically negated by the 32 point wOBA boost from gaining the platoon advantage against a lefty.

That brings us to a key principle, though. The pinch hitter must be at least as good as the hitter he is replacing for the move to not be a net-negative. Ideally, he should be better than the hitter he’s replacing for the move to actually have a positive influence on run expectancy.

How many right-handed hitters are better than the Cardinals’ lefty options? Probably not many. In terms of left-handed bats, the Cardinals have Lars Nootbaar, Brendan Donovan, Nolan Gorman, and Alec Burleson. 3 of those players are regular starters and the fourth - Alec Burleson - is getting regular playing time while Nootbaar is out. All 4 are likely above average hitters this year with the potential to be well above average.

(The Cardinals do have 2 switch hitters in Tommy Edman and Dylan Carlson but both players are better as right-handed hitters which means that they will already have the platoon advantage against lefties while hitting from their stronger sides.)

There are few righties who are going to be better choices than any of these hitters. Andrew Knizner isn’t. Paul DeJong (when healthy) isn’t. Taylor Motter probably isn’t. Juan Yepez only had a .299 wOBA against lefties last year so he probably doesn’t have a case either.

Essentially that narrows it down to regular starters like Nolan Arenado and Paul Goldschmidt who could add value as pinch hitters when they have the day off.

It’s okay to be more aggressive with using pinch hitters when there’s a lefty on the mound but only if the pinch hitter is at least as good as the hitter he is replacing and that scenario simply isn’t a very common occurrence.

Rule #3 - When pinch hitting to gain the platoon advantage against right-handed pitchers, the pinch hitter must be substantially better than the hitter he is replacing for the move to have a positive effect on run expectancy

We can do a quick calculation to figure out just how much better a pinch hitter needs to be for a move to make sense. Let’s take the 34 point pinch hitting penalty and subtract 10-15 points from that penalty due to gaining the platoon advantage to get a new pinch hitting penalty in the range of 19-24 points of wOBA.

I’m going to round up and say that the pinch hitter should be at least 25 points of wOBA better than the hitter he is replacing. And my reason for rounding up is simple.

The point of pinch hitting is to improve a team’s chances at scoring runs. Merely keeping the chances unchanged is just making a move for the sake of making a move. It’s not a benefit; it simply doesn’t change anything. And I would say that it may even be a net-negative because it burns one player from the bench without offering any improvement.

The scenarios here are pretty limited. Below I have listed every left-handed hitter on the team and their wOBAs. (Note: For switch hitters, I listed their wOBA as a left-handed hitter)

In this table, I have also subtracted each player’s wOBA against right-handed pitcher by 25 points to show what their expected wOBA would be as a pinch hitter with the platoon advantage. Essentially, you can use that to show the highest possible wOBA worth replacing when using each hitter.

So, for example, this means that Donovan should only be pinch hitting for a right-handed hitter when that hitter has a .324 wOBA or worse against right-handed pitching. Thus, you can see that the options here are going to be pretty limited.

To begin with, Donovan is a regular starter. So is Nootbaar. So is Gorman. These players would only be available to pinch hit when they aren’t starting, which means the opportunities will be rare, but it’s also hard to find a hitter in the Cardinals lineup with a wOBA worse than .324 against right-handed pitching. Andrew Knizner comes to mind. So does Paul DeJong (when he returns to the roster). Maybe Taylor Motter falls into that bucket too. Beyond that, I can’t think of anyone.

Suffice it to say that, when there’s a right-hander on the mound there are very few situations in which pinch hitting will be beneficial.

Final Thoughts

Before I move on to evaluating Oli Marmol’s pinch hitting decisions this year, I want to cover a few possible exceptions. I’ve laid out some basic ground rules that should apply most of the time but there are times when I would be willing to look past them.

For instance, if Nolan Gorman comes to the plate against a left-handed pitcher who likes to use his fastball up in the zone, I could be persuaded to use a (slightly) worse hitting right-hander as a pinch hitter. Or if a player is 3-for-3, maybe you let him hit instead of using a big bat off the bench. That goes for all hitters who are hot.

Injuries can also change the equation. If a player is playing hurt (i.e. Dylan Carlson in 2022) it may be better to put someone else at the plate.

Individual circumstances and individual matchups always need to be considered as they can change the equation, but, in general, it’s a good bet to stick to the numbers.

Evaluating Oli Marmol

So, using these rules, how effective has Marmol been at deploying pinch hitters (or deciding not to)? In my assessment, he’s done okay.

When pinch hitting, there are essentially 3 scenarios

1. Gain the platoon advantage against a lefty
2. Gain the platoon advantage against a righty
3. Remain at a platoon advantage/disadvantage

Scenario #1 has already happened 6 times this season and scenario #3 has happened once. Let’s dive each occurrence to determine if a pinch hitter was beneficial or not.

4/2 - Tyler O’Neill (RHH) pinch hits for Alec Burleson (LHH) against Tim Mayza (LHP)

I can see the argument for this one but a lot is dependent on how the Cardinals view each player. It is very possible that O’Neill is a better hitter than Burleson and, as we know from rule #2, it’s okay to pinch hit with a better hitter to gain the platoon advantage against a lefty.

Come the end of the season, Burleson may be the better hitter but it passes the test. I would maybe quibble with pinch hitting for someone who’s 3-for-4 on the day, but this was a fine move.

4/3 - Dylan Carlson (RHH) pinch hits for Nolan Gorman (LHH) against A.J. Minter (LHP)

I’m good with this one too. Carlson had a .368 wOBA against lefties last year while Gorman had a .306 wOBA.

Gorman was 2-for-3 with a walk on the day but this move checks all the boxes. The pinch hitter is the better hitter by a large margin and gains the platoon advantage against a lefty. Good move.

4/4 - Brendan Donovan (LHH) pinch hits for Taylor Motter (RHH) against Joe Jimenez (RHP)

I’m willing to say that Donovan is a substantially better hitter than Taylor Motter and this is a move that gave the Cardinals the platoon advantage. The difference here is that a righty was on the mound and that makes the platoon advantage less important.

So the question here is - Is Donovan 25 points of wOBA better than Motter? Thus, the question is essentially - Is Taylor Motter better or worse than a .324 wOBA hitter against right-handed pitchin?

I will hedge my bet towards worse but with the power that Motter has found in the last two seasons, it’s possible that he does prove to be an above average hitter. So, I’m okay with this decision even if I don’t think it moves the needle much.

But the calculation gets a little more complex because the Braves pulled Jimenez for a Dylan Lee, a lefty, as soon as Donovan came into the game. Since Marmol likely knew that was coming, that means that he put a better hitter in the game but lost platoon advantage to a lefty pitcher.

That brings up another complication which is the fact that Donovan is a platoon neutral hitter as he had exactly the same wOBA last year against both lefties and righties.

Honestly, I have no idea what the verdict should be here. I think I’ll give Marmol the benefit of the doubt considering the fact that Donovan is platoon neutral and a better hitter than Motter but it’s never a great idea to cede the platoon advantage to a lefty pitcher, even if that fault isn’t entirely Marmol’s.

4/5 Willson Contreras (RHH) pinch hits for Alec Burleson (LHH) against Dylan Lee (LHP)

This one is easy. The Cards gained the platoon advantage against a lefty and brought in a better hitter. Good move.

4/5 Tyler O’Neill (RHH) pinch hits for Andrew Knizner (RHH) against Dylan Lee (LHP)

Tyler O’Neill had a .346 wOBA and Andrew Knizner had a .232 wOBA against lefties last year which makes this a great move as that 114 point gap is more than three times larger than the 34 point pinch hitting penalty.

4/9 Taylor Motter (RHH) pinch hits for Brendan Donovan (LHH) against Hoby Milner (LHP)

This was not a good move. At all. The Cardinals gained the platoon advantage against a lefty but they didn’t put a better hitter at the plate. At the time, this felt a bit like making a move just to make a move and after further review, my conclusion hasn’t changed.

4/9 Willson Contreras (RHH) pinch hits for Andrew Knizner (RHH) against Matt Bush (RHP)

This is an easy one to consider. Is Willson Contreras 34 points of wOBA better than Andrew Knizner? The answer is yes. Last year, Contreras’s wOBA against right-handers was 42 points higher than Knizner’s.

This wasn’t exactly a slam dunk move that had a big increase on the Cardinals run expectancy but it was still a good move.

Conclusion

To answer the question I posed in the title, 3000 words later, the Cardinals are not pinch hitting too much.

So far this season, Oli Marmol has done a good job at bringing in pinch hitters in the right situations. He’s made the move 7 times in the first 9 games and only 1 of those moves was a bad idea according to the numbers.

This is something I’ll be tracking going forward and if you want to track it as well, I have a few things for you to remember:

1. Pinch hitting solely for the sake of gaining the platoon advantage is a bad idea
2. Pinch hitting conditions tend to be more ideal with a lefty on the mound
3. If not changing who the platoon advantage, belongs to, the pinch hitter must have a 34 point advantage in wOBA in order for it to be a good move
4. If gaining the platoon advantage against a lefty, the pinch hitter must simply be a better hitter in order for it to be a good idea
5. If gaining the platoon advantage against a righty, the pinch hitter must be around 25 points of wOBA better in order for it to be a good move

Thanks for reading, VEB. Have a great Tuesday!