2020 Review: Hitter O-Swing% Decliners by Mike Podhorzer November 19, 2020 Yesterday, I identified and discussed the hitters that improved their O-Swing% the most versus 2019. Today, I’ll check in on the other side of the ledger. While I titled this post “decliners”, what that really means is a decline in skill, assuming a lower O-Swing% is representative of greater skill. So these are the hitters whose O-Swing% increased the most versus 2019. O-Swing% Decliners Name 2019 BB% 2020 BB% BB% Diff 2019 O-Swing% 2020 O-Swing% O-Swing% Diff Byron Buxton 6.4% 1.5% -4.9% 37.2% 51.2% 14.0% Stephen Piscotty 7.4% 5.3% -2.1% 35.4% 45.3% 9.9% Adam Eaton 9.9% 6.8% -3.1% 28.2% 36.5% 8.3% Manuel Margot 8.6% 8.2% -0.4% 25.0% 32.7% 7.7% Christian Walker 11.1% 7.8% -3.3% 28.2% 35.5% 7.3% Andrew McCutchen 16.4% 9.1% -7.3% 17.7% 24.9% 7.2% Robbie Grossman 12.2% 10.9% -1.3% 18.9% 25.9% 7.0% Bo Bichette 6.6% 3.9% -2.7% 38.6% 45.5% 6.9% Omar Narvaez 9.8% 12.7% 2.9% 28.9% 35.7% 6.8% Albert Pujols 7.9% 5.5% -2.4% 32.9% 39.6% 6.7% Luke Voit 13.9% 7.3% -6.6% 26.6% 33.3% 6.7% Hanser Alberto 2.9% 2.2% -0.7% 47.6% 54.0% 6.4% Jesus Aguilar 11.7% 10.6% -1.1% 29.8% 36.0% 6.2% Jonathan Villar 8.5% 9.2% 0.7% 30.8% 36.8% 6.0% It was another wild performance from Byron Buxton whose early-to-mid September hot streak resulted in an ISO above .300 and a HR/FB rate double his career average. But his skyrocketing O-Swing% ended up ranking second in baseball among those with at least 100 plate appearances. Oh, and he easily led baseball with the highest Swing%, at a crazy 64.3% (league average was 45.9%). Buxton swung at everything during his small sample performance, and surprise, surprise, it resulted in a puny 1.5% walk rate. Since he got on base at just a .267 clip, he only swiped two bases in three attempts. He still has posted a 400+ plate appearance season just once, so he’ll once again be a dart throw. Stephen Piscotty’s plate discipline suddenly fell apart, pushing him from deep mixed and AL-Only option to essentially worthless. With a .296 wOBA in his last 564 plate appearances, you wonder how the Athletics are going to weigh his performance versus his remaining contract. I’m not sure what happened to Adam Eaton, as most of his underlying skill metrics look pretty normal, so it was just a matter of swinging a lot more often. He remains a risky choice in his upcoming age 32 season as small declines in multiple areas could easily mean single digit homers and steals, and little mixed league value. Manuel Margot’s .301 wOBA was actually the second best mark of his career, despite his highest O-Swing% outside his 37 plate appearance debut in 2016. Margot’s excellent fielding should keep him from becoming a full-time bench player, but it’s hard to be a Rays hitter and expect every day at-bats. Be aware that he posted his best strikeout rate, even though his SwStk% jumped to a career worst. Christian Walker’s O-Swing% jump was more a result of his major improvement in 2019 that regressed back to previous levels than a step back in skill. Of course, the sample size before 2019 was pretty tiny, but given that the denominator is pitches seen outside the strike zone, the sample is actually larger than you think given the paltry plate appearance total leads you to assume. Overall, the biggest question is that of his home run power, as his HR/FB rate plummeted into the low teens from just over 20%. Where that lands next season will determine whether he’s replacement level in shallow mixed leagues or a reasonable choice as a starter. We don’t have much history for Bo Bichette, but it’s still worth noting that his O-Swing% took a step back this season over a small sample. It led to a pretty pathetic 3.9% walk rate, which is no good for his stolen base potential. Still, there’s obviously a ton to like here. It’s pretty surprising to find Luke Voit’s name here after posting a .393 wOBA and leading baseball in home runs. It’s pretty crazy that he hit one more home run this season in about half the at-bats as 2019. In addition to the jump in O-Swing%, he also swung at pitches inside the zone more, so he was simply more aggressive. Interestingly, he also made significantly more contact on each of those pitch types, entirely explaining why his walk rate was nearly cut in half, while his strikeout rate also greatly improved. Is he the 2021 Pete Alonso, going from elite slugger to just another home run hitter with an iffy batting average or does he hold onto more of his gains? Jonathan Villar was one of just two hitters on this list whose walk rate actually increased, despite the jump in O-Swing%. But a complete loss of power resulted in a .266 wOBA, the lowest mark of his career. That might cost him a chance at a starting job in 2021, meaning he could enter the season as a utility player. Because he still owns that exciting speed and is willing to use it to steal bases, he obviously shouldn’t be forgotten about.