Should Tommy Edman abandon switch hitting?

In 124 of the 162 games played last season, Tommy Edman was the leadoff hitter. He briefly lost his role as the leadoff hitter, but regained it relatively quickly. I was under the mistaken impression that Dylan Carlson struggled in the leadoff role, that his power was sapped there and he focused more on OBP. That is not born out in the stats though. He had a 107 wRC+ on the strength of power, with a .206 ISO, batting 1st. His .314 OBP wasn’t much better than Tommy Edman’s .312 OBP batting leadoff. But it was quite a bit better than Edman’s 93 wRC+ leading off.

Now, I will state right here that I don’t believe hitters perform differently based on where they are in the lineup. I mean they literally perform differently, just because baseball is a random occurrence of events and we’re mostly dealing with small sample sizes, especially so over one year. I’m just using those stats in the context of understanding the roles being flipped, and then returned to the original.

Tommy Edman is a bad leadoff hitter for one reason and one reason only. It’s not on-base percentage. I know I know you probably assumed I would say that. I don’t think he would be an especially good leadoff hitter, but I think Edman could probably be expected to carry an average OBP or better in the future - he had a .291 BABIP, an xwOBA higher than his actual wOBA, and his Steamer projection calls for a .320 OBP. Like I said, not especially good, but it’s not like the Cards have a ton of options after the power hitters with a better than .320 OBP at this very moment.

Now what makes him a bad leadoff hitter is that he is below average against right-handed pitchers. Mike Shildt, though not a direct reason he was fired, seemed to not understand basic splits for some reason. Or at least that they didn’t apply to Edman, because he was a switch hitter. Edman is a fantastic leadoff hitter when a lefty is pitching. He’s truly an abysmal option when a right-handed pitcher is pitching.

I believe in using as large a sample as possible, so I will choose to focus on the splits of his career and not simply his 2021 season. For his career, Edman is a 92 wRC+ hitter against RHP, 127 wRC+ against LHP. His Steamer projection calls for a 99 wRC+ while his career wRC+ is 100. The 92 figure is more or less what you should expect from him against RHP then. In theory anyway.

Splits are a funny thing. Let’s say a left-handed batter has somehow a better wRC+ against LHP than RHP, and he has what appears to be a substantial amount of PAs to support that. We’ll go with 400. According to The Book, you need to regress that number against 1,000 PAs of league average splits against LHP, because over a long sample size (longer than 400 PAs obviously), left-handed batters being better against lefties just really isn’t much of a thing. Not that a left-handed batter can’t be above average against a left-handed pitcher, but they will undoubtedly be a worse hitter than if they only faced right-handed pitchers.

I bring this up because Tommy Edman is a switch hitter. Switch hitters require much less of a sample size. Once a switch hitter reaches 600 PAs against a LHP, you have a pretty good idea of their platoon skill. Edman does not have 600 PAs against LHP. He has 290 PAs. So his platoon skill is still technically unknown. He does have minor league data, but that’s not as good as MLB data.

This question has been posed before, but I do think it’s worth a look: should Edman abandon switch hitting in favor of being a right-handed batter at all times? I thought I’d take a look at the numbers to see if it’s worth a try. It’s not near as simple as “just look at what his splits are.”

For starters, it seems VERY unlikely to me that his splits can be taken at face value. His “true” splits are of course unknowable for now, but I would peg his numbers against RHP as probably better than he’s shown, and his numbers against LHP as worse than he’s shown. By how much is the question, but I do think if he stays a switch hitter, and reaches that magical 600 PA threshold, his LHP splits will be worse than 127, his RHP will be (slightly) better than 92. So I just want to stake that claim right there. (If Edman isn’t a 100 wRC+ hitter going forward, his RHP splits aren’t going to be better. I’m speaking relative to his LHP numbers moreso)

I’m going to do a very simple thing with figuring out whether Edman should abandon switch hitting: I’m going to give him 310 PAs against LHP where he’s an equal hitter against LHP and add that to his current disparity so he reaches 600 PAs against LHP. Edman is certainly better against LHP, but for the sake of argument, I want to see how the numbers come out. Then I will compare it to how he’d do as the typical right-handed hitter with splits. Based on this difference, we can determine if it’s worth it.

The first part of this will be relatively easy actually. I’m going to pretend that Edman will remain a 100 wRC+ hitter, which is a little above what I’d peg him as, but is hardly unreasonable. So his remaining 310 PAs get a 100 wRC+ performance both as a right-handed hitter and a left-handed hitter. I suppose to be fair, I need to give him 1,000 PAs against RHP since he need 973 PAs against RHP before he got to 290 against LHP. Here are his numbers:

LHP - 113 wRC+

RHP - 96 wRC+

That is still a pretty big difference for a switch hitter who shouldn’t be as affected by splits. And like I said, going forward, there’s really no reason to think he would be equal against both RHP and LHP. Okay what are his differences between RHP and LHP if he was the typical right-handed batter? The typical difference in wOBA between a RHP and LHP is 6.1% according to The Book. With a league average hitter that results in:

LHP - 111 wRC+ (.333 wOBA)

RHP - 98 wRC+ (.312 wOBA)

Well if the story ended there, it would absolutely not be worth it. That is not much of a difference at all. But as I said earlier, Edman seems like a really safe bet to not be equal against RHP and LHP. So instead of regressing the remaining PAs to get to 600 as equal, let’s treat him as your average right-handed hitter for his remaining 310 PAs. Edman, despite being a switch hitter, having similar splits as your average right-handed hitter is certainly more plausible than saying he’s exactly equal, given his MLB and minor league data.

LHP - 119 wRC+

RHP - 95 wRC+

That is definitely a bigger split, but I will point out the LHP part of the equation isn’t really the relevant part. It’s the RHP part. We know how good he is against LHP. We don’t know exactly how good he is. But he will still be facing LHP as a right-handed batter regardless. That number is essentially irrelevant.

So should Tommy Edman abandon switch hitting?

I really don’t think so actually. From where I’m sitting, there is just not a ton of upside. Edman seems extraordinarily unlikely to buck the trend of the how right-handed hitters typically do against right-handed pitchers. In fact, I think there’s more reason to think he’d have a stronger split than the typical right-handed batter. Be kind of weird if a guy who has four total plate appearances as a righty against right-handed pitchers in his professional career somehow has less of a weakness against RHP than normal, no?

So it seems to me a pretty likely outcome to him becoming a full-time RHB is... the same exact place he’s likely to be as a switch hitter. It wouldn’t be a bad idea to dip his toes in the waters of being a RHB against RHP against pitchers who are worse against right-handed batters. If a RHP is better against lefties, then the equation is a bit more tilted in favor of Edman choosing to bat right-handed. But for the average right-handed pitcher who is worse against lefties, I genuinely don’t think there’s much upside to be gained. Things may change when he gets closer to that 600 number, but for now, I got to keep him at switch hitter.