Hitter xwOBA Underperformers — May 11, 2022, A Review

In mid-May, I reviewed a group of hitters who had most underperformed their Statcast calculated xwOBA marks. While we all acknowledge that xwOBA isn’t perfect, it’s the best all-encompassing estimator we have, so it’s a good star to identifying players who are underperforming and overperforming. Now, I want to find out how these xwOBA underperformers ended up doing over the rest of the season. Did their wOBA marks rebound close to their early season xwOBA marks? Did their skills improve or decline so their rest of season xwOBA marks varied, making the RoS and early season comparison apples to oranges? I’m always curious how my lists turn out, so let’s dive in.

This is a fascinating table of results. I highlighted those that rebounded close to their early xwOBA marks in yellow, and those that failed to in red. Of the 11 hitters listed, less than half (five) actually rebounded. So you might think that this target list of rebound candidates failed. You would be wrong. I think the more important column is the last one, where I indicate whether the hitter underperformed again. Remember, the skills driving wOBA and xwOBA vary throughout the season. A true talent .350 wOBA hitter isn’t going to post exactly a .350 wOBA every week of the season. All 11 hitters either just missed their RoS xwOBA marks (you might quibble with some of my calls of having not underperformed again, but to me, they were close enough to consider not underperforming), or outperformed. That’s quite the rebound after such significant underperformance over the first month or so of the season.

Remember, xwOBA is not a projection, but rather a descriptive metric that calculates what the hitter’s wOBA would be with neutral luck, given the underlying skills driving that calculation. So if a hitter continued to stink over the rest of the season, but his xwOBA also validated the poor performance, the metric wasn’t wrong early on when it calculated the hitter’s xwOBA as significantly higher than his actual. The hitter merely became worse, and there was no way his early xwOBA could have predicted that.

Whit Merrifield was the league’s biggest early season underperformer, and it wasn’t particularly close. This was a problem for fantasy owners, as he was always far more valuable in fantasy leagues than in real baseball. So real baseball struggles could have ended up costing him playing time. Once he was shipped off to the Blue Jays, initially, it did. But then injuries struck and he got hot at the right time, which returned him as a fixture in the lineup. While the 0 homers early on affected his output, it was mostly a .152 BABIP that did him in. He ended up finishing with a .276 mark, so clearly his BABIP fully rebounded. He even finished with a 6.6% HR/FB rate, higher than 2021, and just below his career average. So it’s safe to say that he fully rebounded over the rest of the season, and he even handily outperformed his RoS xwOBA. Unfortunately, his steals plummeted after he surprising stole 40 bases in 2021, so he still finished as a disappointment.

Jesse Winker was definitely much better over the rest of the season, but still fell far short of initial expectations. What happened to his power?! Of course, we figured he would lose some of it upon moving from the best left-handed home run park in baseball to a park that suppresses homers from left-handers. But his HR/FB rate getting cut in half?! I didn’t expect the decline to be that dramatic. He also posted a career worst BABIP, so even though his BABIP did improve, it didn’t do so enough to erase his early season struggles.

Jonathan Schoop was a good example of a hitter who stunk all year, but he technically did rebound over the rest of the season, as his wOBA did nearly meet his xwOBA during that time. For someone with terrible plate discipline, it’s going to be a real crapshoot on whether he rebounds.

It was mostly a BABIP thing for Gleyber Torres, which he corrected over the rest of the season. While he still hasn’t come close to the power he showed during his first two seasons, he did return to being one of the better fantasy second basemen, as he got back to the 20 homer level and also continued to steal double digit bases. What’s crazy is that his HardHit%, EV, maxEV, and Barrel% are all higher than his 2018 and 2019 seasons, and yet his HR/FB rate finished significantly below those years.

While Alex Verdugo’s HR/FB rate collapsed over the rest of the season, his BABIP surged, and he posted a wOBA right in line with his xwOBA from early in the season and over the rest of the season. It’s too bad the counting stats weren’t there to make a difference in fantasy leagues.

Ramón Urías rebounded nicely over the rest of the season, posting a wOBA just short of his early season xwOBA, as his HR/FB rate spiked. It’s too bad injuries cost him some time, and his walk rate slipped, but he generally delivered as I expected on a per-PA basis.

Kyle Tucker was a star early on from a skills perspective, but those then slipped the rest of the way and his wOBA matched those rest of season skills. Both his BABI and HR/FB rate finished relatively close to his early season marks, so he didn’t get a whole lot better, but with 30 homers and 25 steals, I think his fantasy owners were still more than satisfied. I still feel like he’s capable of far more.

Giancarlo Stanton’s season went similarly as Tucker’s, as he failed to post results that matched his early season xwOBA, and then he wasn’t able to maintain those skills, so his rest of season xwOBA fell, and then he was able to match it. Stanton’s BABIP over the rest of the way actually fell precipitously, as he finished with just a .227 mark after a .303 mark early in the season. He did offset the drop somewhat by upping his HR/FB rate though, so the power was fine, but he batted just .211 thanks to that ugly BABIP.

It was a completely lost year for Yasmani Grandal, whose power completely vanished. How much did injury play a role? Entering his age 34 season, how much of a rebound should we realistically expect?

Speaking of age-related decline, we knew Nelson Cruz couldn’t hit forever! While he did underperform early on, his xwOBA was still far below what we’ve become accustomed to. He did rebound most of the way over the rest of the season, but his skills remained well below what we expected. His BABIP did fully rebound, but the power actually declined further the rest of the way. It’s hard to believe given a 113.8 maxEV and 9.3% Barrel% that his HR/FB rate would be cut in half. Will this end up being the final season of his career or will he get another chance. If the latter, how much, if any, does his power rebound?