Three up, three down: Using xwOBA to assess six Yankees hitters

Longtime readers know that one of my favorite stats by which to judge and assess player performance is xwOBA, or expected weighted on-base average. wOBA alone considers the actual outcome of a play, such as single, double, triple or home run, and it weights each of them in proportion to their run value. We can’t value a home run the same way as we do with a single, of course.

However, xwOBA tries to eliminate factors such as defense and ballpark, instead focusing on exit velocity and launch angle, adding walks and strikeouts, too. To wOBA, a sharply-hit rocket to center field for a single is the same as a chopper that found its way to left field through the hole. That’s not the case with xwOBA, which helps us have an idea about the hit probability of a ball in play.

Both stats, but especially xwOBA, can help us try to predict future performance. We should emphasize the word “try,” as it isn’t an exact science. Judging by wOBA and xwOBA, here are three Yankees that were fairly unlucky in 2019:

Aaron Judge

The Yankees’ right fielder had a .382 wOBA, but his xwOBA was .401. Judging by his elite exit velocity and hard-hit rate, he should have had better numbers last season and should be counted on to put his usual elite numbers in the power department (he slugged .540, but his xSLG was an even better .580) if there is a season in 2020. And if he’s healthy, of course. His -.019 differential ranks him 45th out of 320 hitters with at least 250 plate appearances.

Gary Sanchez

Sanchez had a -.017 differential between his wOBA (.346) and his xwOBA (.363) which means that he was a little bit unlucky given his batted-ball profile. Actually, Sanchez’ Statcast data suggests that he can be very dangerous in 2020: he led the league in barrel percentage with 19.1, he had a very healthy 91.0 mph in average exit velocity, and his .552 expected slugging was in the 92nd percentile. He won’t bat .300, but consider for a second the fact that he hit 34 homers in just 106 games (!) and he has the potential to top that.

Luke Voit

Voit was actually on the way of having a great season until his core injury derailed his 2019. As far as luck goes, the Yankees’ first baseman/designated hitter was just a tad unlucky last year, with a -.005 differential between his wOBA (.360) and xwOBA (.365). Voit’s 13.2 barrel percentage was in the top nine percent of the league, and his 13.9 BB% was also elite. His xwOBA was in the 86th percentile, indicating that, with health, he can mash in the middle of the Yankees’ lineup in a shortened season.

And here are three Yankees that were on the other side of the spectrum: they had luck on their side:

Brett Gardner

Yankees fans love Gardy, and the sentiment is mutual. However, it is very likely that 2019 goes down as the best season of his career from an offensive standpoint. The +.043 differential between his inflated wOBA (.344) and his xWOBA (.301) is the fifth largest in MLB among batters with at least 250 plate appearances, and there is a huge disparity between his slugging (.503) and xSLG (.372). Simply put, Gardy took advantage of the short right field porch and, with quite a bit of luck, had a fantastic season numbers-wise. Gardner’s average exit velocity, hard-hit percentage, xBA, xSLG and barrel percentage were well below average.

Mike Tauchman

Tauchman’s defense and baserunning make him a quite valuable outfielder. He carries a very good bat, too, just maybe not 2019-good. He ran a +.041 differential between his wOBA (.364) and his xwOBA (.323), the ninth-largest in the league among batters with a minimum of 250 plate appearances. He batted .277 and slugged .504, but expected stats say that he should have had .248 and .412, respectively.

Gleyber Torres

Torres hit 38 homers in 2019. He had great season. However, he was a tad on the lucky side: with a .359 wOBA and a .341 xwOBA, he generated a +.018 differential. To fully unlock his potential, he has to increase his hard-hit rate, as he was in the 33rd percentile in MLB. His ceiling remains sky-high, though.