It's been a while since we delved into xBA. We're now halfway through the season so it's a good time to see whose batting average is due for course correction, whether it be positive or negative.
Often, although not always, players with sizeable discrepancies in BA-xBA are due for regression. Identifying these outliers can be extraordinarily helpful for fantasy baseball managers looking to gain an edge by buying low, selling high, or streaming players at the right time. Here are three such players in each category.
All Statcast metrics are current as of June 27, 2021 and data/graphs are taken from BaseballSavant.mlb.com.
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BA-xBA Overachievers
The following players have a batting average far higher than they should according to Statcast. A decline may be in store over time. We've recently examined the top overachiever, San Francisco's Steven Duggar, as someone who has inflated performance against fastballs. Tucker Barnhart ranks third on this list but is not truly fantasy-relevant outside of two-catcher leagues. Here are some other players worth examining.
Jean Segura, Philadelphia Phillies
.062 BA-xBA
Segura has been remarkably consistent throughout his Major League career, with 2020 looking like a blip on the radar when his average dropped to .266 after four straight seasons over a .280 AVG. Now, he's batting a career-best .332 and dropped his K% down to a more characteristic 14.3%. His xBA is a solid .270 that's very much in line with his past few seasons, but that means we should expect at best a .300 average once his .378 BABIP regresses closer to his .320 career mark.
Segura is currently on the 10-day IL with a groin strain that could keep him out another week. This makes him a tempting buy-low candidate for those in need of a boost in batting average. The opposite holds true, however, as he should be avoided or traded away whenever possible. His 20-steal upside isn't there anymore and a groin injury makes it even less likely he'll be running.
Randy Arozarena, Tampa Bay Rays
.051 BA-xBA
Arozarena continues to lie among the extremes in Statcast world, mostly on the lower end. His .214 xBA is in the seventh percentile and has been below the MLB average for most of the season.
He is batting 51 points better than expected and slugging 69 points above expectation. The power-speed combo is still there, but the launch angle issue still exists and will hold him back until it is corrected, if ever.
Marcus Semien, Toronto Blue Jays
.038 BA-xBA
Never one known to post a high xBA, his .238 mark is actually third-highest of his seven-season MLB career. He could keep outperforming it as he did in 2019 when he batted .285 compared to a .257 xBA, but the difference is a little higher this time.
Inexplicably, Semien is hitting offspeed pitches at a .378 clip this year after dropping off big-time in that area last year.
Can he keep it up? The law of regression says no, but unless he suddenly hits a cliff, it shouldn't affect his bottom line in terms of fantasy value.
BA-xBA Underachievers
Here are the players who may be of interest to those looking for an under-the-radar waiver wire add or simply looking for good news on a struggling starter.
Kyle Tucker, Houston Astros
-.057 BA-xBA
Not that anyone is panicking over Tucker because his average is at .265 midway through the season, but Statcast confirms that he's a star even if his statline doesn't show it.
Notice the xBA in the 99th percentile that doesn't jive with his batting average. A .272 BABIP is to blame. He's got a 49.3% Hard% and 28% line drive rate, so he's truly earned an elite average. If there's something to be disappointed in, it's the five steals in six attempts. Houston is sixth-lowest in SB attempts per game, so the lack of steals may hold Tucker back from being a fantasy superstar. It won't be his average by year's end.
Anthony Santander, Baltimore Orioles
-.040 BA-xBA
The Santander breakout may have to wait another year. After a blazing stretch in 2020 where he put together an 18-game hitting streak and was up there with the league leaders in RBI at one point, Santander hasn't found his stroke since. To start this season, he was down to a .196 average before hitting the injured list on April 20. May was looking promising but he's on the downslide again.
His expected average has remained above league-average throughout this span, though. His 100-PA rolling xBA is at .292, far higher than the MLB average of .243.
His xSLG is sitting right at league average, but more base hits will ultimately mean more R+RBI. Santander has been a bust thus far, but is someone to watch as he's been dropped in many leagues and is now only 34% rostered across Yahoo!
Max Kepler, Minnesota Twins
-.054 BA-xBA
Two separate stays on the IL have kept Kepler out of action part of this season. When in the lineup, he's slashed .200/.293/.394 with six home runs, 26 RBI, and 23 runs in 160 at-bats. His saving grace has been seven steals that have come out of nowhere, already marking his career-high. Kepler's value should lie in his power numbers and run-scoring potential based on his spot at the top of the lineup. Instead, he's struggled and been placed between the 5-7 spot in the order since returning from his latest injury.
We don't expect much as far as batting average for a career .235 hitter but .200 is unrosterable. There should be improvement on the way, as he's underperforming his xBA by 54 points and his xSLG by 45 points. His 90.9 MPH exit velocity is the highest of his career as is his 9.8% Barrel rate. Kepler is seeing the ball well and making quality contact, so the base hits should start dropping in soon enough.