Matt Carpenter’s Rehab

The recent West Coast road trip was a disaster. When the starters were good, the offense was bad. When there were leads, they were squandered. Michael Wacha appeared. None of this is particularly what you want to see as a Cardinals fan. One thing that threatened to be a big story, though, before kind of fizzling, is Matt Carpenter’s return.

You see, Carpenter had been capital-b Bad in his minor league rehab. Two hits in 33 plate appearances bad. .273 OBP, .115 slugging percentage bad. It wasn’t as though he’d been good in the majors before getting hurt, either. Letting him play was controversial, and plenty of people wanted the team to just run with Tommy Edman and let Carpenter work himself out in the minor leagues.

Edman’s outfield adventures aside, though, the team has been better off with Carpenter playing third base. He’s been completely fine since returning (though he’s day-to-day as I write this before Friday’s game), going .286/.412/.286 over the 17 plate appearances he got this week. That, of course, is way too small of a sample size to say much about. An 11.8% walk rate and 23.5% strikeout rate isn’t anything we haven’t seen Carpenter do before, and it’s hard to argue that Edman would have done better than the 103 wRC+ Carpenter’s line works out to. Edman, in fact, has a -14 wRC+ over roughly the same amount of playing time in the month of August.

So, the reflexive fearmongering over Carpenter’s lackluster rehab doesn’t seem to have been justified, at least so far. That made me wonder, though — should we have looked a little more closely at the minor league numbers? The slash line was ugly, there’s no doubting that. Still, Carpenter has plenty of 33-PA stretches where he has a low BABIP and only props up his production via walks. There’s nothing particularly interesting about that. Is there anything more we could have said by digging into the numbers a little more?

While minor league data isn’t always the easiest to come by, I cobbled together pitch-level data for the 161 pitches Carpenter saw on his rehab assignment. What was I looking for in the data? Honestly, I don’t know. If anything popped out, though, I wanted to be able to point at it while I complained about the front office.

First, I looked at contact rate. Carpenter hasn’t been a high-contact hitter since around 2015, when he turned into a power threat, but he’d been declining even further in 2018 and so far this year, dipping below 80% contact in both years, a mark he’d never fallen short of before. Some of that is related to teams going all sliders all the time against him, but he honestly just hasn’t looked completely right at times this year. He’s also had a 72.7% contact rate since returning from injury, which made me think that hey, maybe his timing was just abysmal in the minors and the team ignored it.

Nope! Carpenter took 54 swings in the minors, connecting on 44 of them. That works out to an 81.5% contact rate, completely uninteresting and not at all showing signs of rust. If all you’d told me is that Carpenter made contact 81.5% of the time in the minors, I would have assumed he was totally fine.

How about swinging strike rate? That’s another place he’s struggled this year, posting a career-high 8.7% rate despite his normal low-swing tendencies. Yet again, no dice. His 10 whiffs in 161 pitches work out to a 6.2% swinging strike rate, exactly his career average. Nothing to see there at all. When he swung, he was doing about what you’d expect with the ball, neither making contact with everything nor whiffing outrageously.

If one thing stuck out about his minor league swings, it’s how few there were. His 33.5% swing rate is on the low end, particularly given that he’d been swinging at 40% of the time in the big leagues this year. That’s not a problem in and of itself though — his 2014 and 2017 seasons were similarly passive, and those worked out just fine. Being passive didn’t hurt him in terms of taking too many called strikes, either. He took 21% of the pitches he saw in the minors for strikes, roughly in line with what he’s done in the last five years in the big leagues. He did strike out looking for half of his strikeouts, but that’s hard to say much about without location data, which I don’t have.

How about his contact quality? There isn’t any Statcast-style data for minor league games publicly available, so I was reduced to looking at balls in play by type. There was good news there, though — Carpenter’s batted ball distribution was excellent. He hit three fly balls for every grounder, two line drives for every grounder. His 33.3% line drive rate is a sign that he was making decent contact, and only three ground balls is excellent news for someone like Carpenter, one of the most-shifted players in baseball.

The three groundballs, of course, were all to the pull side of the field. That seems unlikely to change given the way Carpenter works. The fly balls, though, were more of a mixed bag. There were three to the pull side, four opposite, and two to center. That’s quite close to what he’s accomplished in the majors, where he’s pulled about 25% of his fly balls since 2015, and far better than what he’d accomplished so far this year, where he pulled only 12%. Pulled fly balls tend to be hit harder, so that’s a good sign.

Line drives were similar. He lined two balls to the pull side, both of which went for hits. That’s where the power generally lies for Carpenter, so it’s good to see him able to get around on pitches that he hits on a line. You’d like to see more in that grouping, obviously, but if I saw someone with a 33% line drive rate, I’d be pretty happy with their batted ball quality regardless of how many they pulled, low BABIP notwithstanding.

Of course, with Carpenter back in the major leagues and performing just fine, this story will quickly be forgotten. There are bigger fish to fry with the team at the moment, whether it’s Mike Shildt’s addiction to playing infielders in the outfield or Cardiac Carlos making the ninth inning more exciting than it needs to be. My point, though, is that this is a place where we have very little visibility, and that we don’t really have reason to doubt the team’s ability to know when hitters are ready to come back.

Looking at Carpenter’s baseball-card statistics in the minor leagues was alarming. In a year where the Cardinals have made a ton of questionable decisions, it’s easy to just assume they’re doing another dumb, overly loyal thing. Look deeper at the data, though, and there’s almost no indication that he was doing anything wrong. Without access to the actual batted ball and location data, which the team has, we can’t say more. Still, this is a spot where we should probably give them the benefit of the doubt.

The Cardinals have made a lot of bad tactical decisions this year. The VEB community has, in the main, been pretty aggressive about pointing them out, which seems to me to be a good and normal function of a fan website. That said, I don’t think bringing Carpenter back to the majors after his rehab was one of those bad tactical decisions. It’s the kind of thing that we could easily forget, but I wanted to point it out because in a year where I’ve often second-guessed lineup choices, this is one where the data was in the team’s favor, even if it didn’t look like it at first glance.