There was a point, amidst the disappointingly-insouciant doldrums the 2021 Braves endured in May and June, that William Contreras was a positive glimmer adrift in a lagoon of blah. Thrust into the starting catcher role despite not making the Opening Day roster due to a bunch of backstop injuries, Contreras hit the ground running. He reached base twice in both of his first two starts of the year, and then went 2-for-4 with a homer in his third game. He had a 153 wRC+ through his first 10 games of the season, and it was still above-average at 117 after 20 contests. This performance wasn’t a tricky small-sample mirage, either, as he was actually underperforming his xwOBA through those stretches. All the way through June 9, Contreras had a 122 wRC+ and a matching set of wOBA/xwOBA at .360. His defense was rough, but a 122 wRC+ catcher with Contreras’ issues behind the plate is still someone above the 2 fWAR per 600 PAs threshold, and that production was a pretty big boon for a scuffling Braves team.
But then, disaster struck. Contreras went o-fer in his next four games (three starts). He managed only two good offensive games after June 9, was hitless in nine of his final 10 games prior to demotion, and failed to reach base in six of his last seven games (aside from an intentional walk, which doesn’t count for hitter value). He was so bad in his last 16 games that his wRC+ dropped from 122 to 76, and he lost 200 percent of his fWAR over that span. (In other words, he went from +0.4 to -0.4.) If you’re a visual person rather than a text person, you can just glance at the below.
Much like how his early-exposure success wasn’t just ball-in-play shenanigans, his collapse was also real. That joint .360 wOBA/xwOBA fell to .148/.195 from June 9 through July 5. Sure, that’s a big xwOBA underperformance, but a .195 xwOBA is real bad too.
The cool thing about Contreras, when he was raking, was that he didn’t seem fazed by now-ubiquitous sliders. He saw a four-seamer, a two-seamer, or a slider over 70 percent of the time through June 9, and had a .398 xwOBA against those pitches. (He struggled with cutters and curves, but rarely saw them.) In particular, his slider heatmap cracks me up.
This is how pitchers attacked Contreras with sliders through June 9:
And these are the ones he swung at:
In other words, and yeah, we’re talking teeny-tiny samples of pitches here, but Contreras got 43 sliders out of the zone through June 9 and swung at 15 of them... but only three were essentially unhittable, while the other 12 were borderline.
Now, to look at the games after June 9. Contreras was still seeing four-seamer/sinker/slider over 70 percent of the time, but his production crashed on everything. The slider, though, was particularly brutal: from .386 to .117. Here’s the slider heat map, with pitchers basically daring him to go fishing.
And yes, go fishing Contreras did. Here’s the heatmap of the sliders he chose to swing at.
Dude. Dude. 37 sliders out of the zone from June 10 on, and he swung at 16 of them. Okay, that’s not a huge increase, from 35 percent o-swing to around 43 percent. But if we’re talking swinging at non-borderline sliders in the “chase” area, the ones batters basically can’t hit, Contreras went from swinging at 3 of 13 (23 percent) to swinging at 8 of 18 (44 percent). Yeah, it’s only a few pitches, but the heat maps are pretty illustrative: even early on, pitchers tried to get him to bite on non-competitive sliders, and he really didn’t. But after a few weeks, suddenly, he was diving over the plate to flail at something way outside. This wasn’t even a case of pitchers adjusting, at least not in any kind of wholesale, dramatic fashion. Instead, Contreras just made it easy for them: he started swinging at the stuff he was taking, essentially becoming a free out in the process.
Notably, Contreras’ overall plate discipline metrics didn’t move that much before and after June 9. The effects are about what you’d expect for a small-ish sample where a guy is doing well in one part and poorly in another. o-swing went from 36 percent to 41 percent, o-contact from 57 percent to 52 percent, overall contact from 69 percent to 64 percent, zone rate from 43 percent to 40 percent, whiff rate from 16 to 20 percent. The point here is less that these are dramatic swings... it’s that his “dramatic swing” was that bizarre chasing of sliders he previously spit on.
To that end, it’s hard to make much of the struggles-wot-got-Contreras-demoted. The slider-chasing wasn’t the only problem, not by a longshot, but it seems like it should be an eminently-fixable one because he had already spent most of his prior 100 PAs not doing it. Even as his seasonal line collapsed, Contreras showed great contact quality (.407 xwOBACON when league average is in the .360s, average exit velocity over 92 mph, a barrel rate nearly twice the league average, a hard hit rate 10 percent greater than league average), so I can’t help but wonder what that line would’ve looked like had he just not swung at sliders he had no chance of hitting. There’d be at least one more walk and one fewer strikeout, and we’re really only talking about eight dumb swings here (two of which were in PAs that still had positive outcomes) so it’s not much, but it’s still kind of interesting to think about.
In any case, Travis d’Arnaud is back now, and this is mostly just a curiosity. But those heat maps, I can’t shake ‘em. What a weird thing to have suddenly happen.