How Will the 3-Batter Minimum Affect the Cardinals?

Quick note before we start this one: I don’t feel all that strongly about the argument contained herein. I’m writing this on vacation, and I wrote really all the words you could imagine this week for FanGraphs, and I’m beat. I wanted to write a complete throwaway article about Kwang-Hyun Kim, but the entire site beat me to it. I even managed to find some Trackman readings from 2019 on him: suffice it to say, he spins his fastball pretty well and his slider well enough, while his curve gets a lot of movement despite little actual spin action; perhaps he’s just really good at maximizing what action he gets. In any case, you’re not getting that article, because it’s been covered. Instead, here, have a lukewarm take I cooked up on the spot. I turned it into 1200 words for you, even. Just don’t expect a great argument.

Hi. I’m a baseball fan. I think my team’s manager doesn’t use his bullpen well enough.

Okay, go ahead, stop me. That’s true of everyone, and it’s silly of me to reflexively think that about the Cardinals. I know, I know, it’s true. And yet -- I think it’s absolutely true of Shildt and the Cardinals. Good news, though -- I think the biggest hole in his game involves overvaluing handedness, and 2020 should fix that problem.

But Ben, you might say. Handedness really matters! Aren’t you always telling us that? Well yeah. Handedness really does matter! Winning the platoon battle goes a long way to winning the overall battle in a matchup, and the Cardinals certainly understand that. In fact, the team was first in baseball when it came to the percentage of the time that a left-handed pitcher had the platoon advantage.

Why am I focusing on that? Don’t all pitchers matter, not just lefties? Well, sure. But the number of platoon-advantaged plate appearances the pitching team has is dependent on the construction of the roster. A team with mostly right-handed pitchers will have a higher number of platoon-edge matchups than a team of all lefties, because more batters are righties. So I’m looking at just the left-handed side of the ledger to equalize things.

One more thing that might goof it up: teams with left-handed starters will inevitably have fewer lefty-lefty plate appearances proportionally, because starters throw to the whole batting order, where there are bound to be more righties. Consider only relief appearances, and the Cards fall all the way to fourth.

This sounds good! The Cardinals are scheming their way to small advantages as well as almost every other team in baseball. There are other problems with this analysis, of course -- a team with only one lefty reliever of note will tend to have a higher proportion of his appearances come against lefties, and so on -- but in general, it’s an okay first pass.

Now, come 2020, this won’t be happening anymore. The Cards finished fourth in baseball in appearances that will be outlawed by the new rule (research is here), and 21 of their 28 pre-September short stints came from two lefties: Andrew Miller and Tyler Webb.

I mean, you’ve watched Cardinals games before. That’s why you’re here. You get that Webb is on the roster to go get lefties. What you might not know is that Shildt used Miller in much the same way in 2019. In fact, you could argue he used Miller *more* that way than he did Webb. He made 12 short appearances last year to Webb’s 9, the fifth-most LOOGY-ish appearances in all of baseball.

Now look, maybe Andrew Miller is bad now, and he’s nothing more than a lefty specialist. That seems wrong to me, though. He’s still projected quite well, and the team clearly brought him in to be an overall stopper, not Oliver Perez with longer arms. His slider was all over the place, but he still profiles as a key part of the team’s bullpen going forward, one of two sure things alongside Giovanny Gallegos and John Brebbia (who is still great).

But here’s the thing: even if the team brought Miller in to be more than a lefty specialist, Shildt didn’t use him that way. He used him like a Tony LaRussa-era Randy Choate; come in, face Juan Soto or Christian Yelich or whoever, and hit the showers. And honestly, the team couldn’t really afford that. Take a look at the bullpen innings in 2019: John Gant labored for 66 innings. Dominic Leone somehow threw 40. Mike Mayers got 19 in. Heck, Michael Wacha even had 12.

The high workload seemed to take something out of Gant, who had been so steady early in the season (even if his underlying numbers were never superb). Leone didn’t look right for most of the year, but he still went out there day after day and threw. Gant needed a rest, but he had to pitch more or less all the time. Why? Miller didn’t soak up enough innings when he came in.

I’m not advocating a return to the Andrew Miller role for Andrew Miller. He’s not really that guy anymore, a multi-inning marvel who can throw an inning or two every other day. At 35, he’s clearly on the downswing, even if his 2019 form isn’t representative of the new normal. But by using one of your highest-leverage arms in short stints in a matchup-dependent fashion rather than in important spots, you force worse arms into bigger spots.

This is all kind of speculative. Maybe Shildt correctly diagnosed Miller as broken, and the usage wasn’t overvaluing a platoon advantage but rather shielding Miller from tough spots. He still did manage 54 innings, even if it took 73 appearances. And he pitched in big spots; his leverage index was third-highest on the team.

So maybe I’m full of it. Maybe all that will happen with the new rule is that the team will use Miller a little differently with no real benefit. After all, I started out criticizing Shildt for his usage, but he put Miller in great spots (both in handedness and leverage) and still got 54 innings out of him. But my sense is that this is wrong, that the team could do better by using him for an inning at a time rather than going batter-to-batter.

Whether it’s helpful or not, it’ll be happening in 2020. And the Cardinals are better-equipped than most to deal with the change. The Cardinals were fourth in the league in short-stint usage, but per a rough formula I came up with, they would hardly give away any wins if they lost the platoon advantage. That’s because Miller doesn’t have terrible platoon splits; he’s surrendered a 5.7% worse wOBA to righties than lefties, roughly in line with league average.

Webb is substantially worse; he’s been excellent against lefties and poor against righties in his career, albeit in small samples. But he’ll be marginalized by the new rule; the Cardinals clearly don’t trust him that much against righties (rightfully so), which means more of his innings will be soaked up by the right-handed half of the bullpen.

Every team in baseball will have to change a little in 2020. But to me, the Cardinals are among the winners in this new rule. Their manager used a high-priced bullpen acquisition as a matchup reliever in 2019. That won’t happen again in 2020 -- rules guarantee it.