It is not a stretch to say that Joc Pederson did not have the 2021 he wanted. Honestly, given his part-time, xwOBA-underperforming 2020, his career has actually descended into somewhat of a rut, not that you’d know it through his hilarious on-field antics. Still, it’s been an unfortunate turnaround for a guy whose career to that point had featured almost entirely above-average seasons. Between 2015 and 2019, Pederson compiled 13.0 fWAR, 66th in the majors among position players in that span. Not elite or anything, but well above average, especially considering that his limitations against same-handed pitching and some injuries limited him to less than 80 percent of what a “full-timer” (600 PAs per season) would have accumulated in terms of playing time. Since then, though, Pederson has managed just 0.5 fWAR across parts of two seasons, both of which were the worst calendar years of his career.
When the Braves traded for, and then subsequently began playing, Pederson in mid-July, I was somewhat surprised by how much he had changed from his earlier iteration. Why? Well, his Braves tenure started with a groundball to short. Pederson did connect on a homer to right-center in the next game, but his other PAs in that game included a pulled grounder, a fly to left center, a pop-out to short, and an infield single against the shift. After that, he had a walk, a grounder single through the shift, a double down the left-field line, and a lineout to center. The point is, he didn’t have a bonafide “pulled ball in the air” until his 17th PA as a Brave (which, of course, was caught just shy of the wall).
This was not really much of a new development for Pederson. While there are different ways to classify what counts as “a ball in the air” and what is “pulled,” his rate of doing so cratered either way. From 2015-2019, between 19 and 23 percent of Pederson’s balls in play were “pulled in the air” per Baseball Savant. In 2020, the rate dipped to under 15 percent, albeit in a shortened-by-the-pandemic season. In 2021, it rebounded a bit to 17.5 percent, but still below the standard he had set for himself. The trend using the batted ball data displayed on Fangraphs is less dramatic, but similar:
Whatever relatively large gap exists between the two classification systems in 2019 aside, the idea is that Pederson’s 2020-2021 have been a break from the norm, and also the seasons in which his hitting has really tanked.
Linking these two things together isn’t really a stretch. League xwOBA for 2021 ended up at .315, improving to .370 on contact. Looking at just pulled contact yields .409 (with a .439 wOBA), which is miles better than either stuff hit to center or the other way. Looking at just contact in the air yields .484. Combine these into a tabular summary, and you get:
Pulling the ball in the air is where it’s at, which makes sense because even independently of one another, pulling the ball and not hitting grounders are the best outcomes relative to their alternatives. Again, Pederson was not elite at his rate of balls in play being pulled non-grounders, but he was pretty good. He did a lot of damage on these types of balls, as is expected.
2020 was a weird year for everyone, and while Pederson’s xwOBA was perfectly fine that year, the “air-pulls” evaporated. Even more strikingly, the quality of those air-pulls tanked as well. In 2021, Pederson rebounded somewhat but not a lot in this regard, while continuing to underperform his xwOBA. When he did actually pull the ball in the air, though, he posted the second-highest wRC+, and highest xwOBA, of his career, reversing whatever happened in 2020 that led to very weak pulled fly balls. The point is, Pederson is still capable of doing massive damage when he pulls the ball in the air, but he hasn’t been doing so anywhere near as frequently as before.
The Braves, as a team, like pulling the ball in the air. Since the start of the 2018 campaign, they rank eighth in MLB in the percent of balls in play that are air-pulls. After three seasons of ranking around the top 10, they were first in this rate among all MLB teams in 2021 (mostly thanks to Ronald Acuña Jr., and then Adam Duvall and Eddie Rosario after they were acquired). Pederson’s rate of air-pulls actually fell after he changed teams, though — driven in part by a massive spike in grounders after the trade that came almost entirely at the expense of fly balls (rather than liners). He did pull the ball a bit more after the trade, but not nearly enough to compensate.
Hitting has a lot of moving parts, both biomechanically and in terms of how different plate discipline and contact stats combine to yield an overall batting line. Joc Pederson was good, not great, at doing a very valuable thing. Then he kind of stopped, and couldn’t get back to it, even when he joined a team that was a big fan of doing that thing. It’s probably something he’s going to have to figure out going forward, though his xwOBA suggests he might be fine if he doesn’t, too — provided he doesn’t underperform it again. Still, if only he could’ve gotten to that 450-plus wRC+ and .650-plus xwOBA more often, it may have made this upcoming free agent market easier for him to navigate. There’s always next year, though.
In the playoffs, Pederson’s air-pull rate rebounded to a massive 28.1 percent. It also exceeded 20 percent in his 2020 championship run, despite the real paltry, small-sample regular season value. It didn’t help his playoff line (too few walks, too many pop-ups), which was worse than his regular season line in both wOBA and xwOBA terms, but it goes to show that there’s little evidence that Pederson can’t hit deep flies to right anymore. It’s just that he didn’t, despite that being a pretty great approach for him. In short: Joc Pederson, pull the ball in the air some more!