One of the bigger storylines of this MLB season so far has been the year-long struggle of 2015 MVP Bryce Harper.
Harper, who had a historically great season (.330/.460/.649 with a 1.109 OPS) last year has looked merely mortal this season, slashing .235/.380.443 with a .823 OPS. It was fair to assume some regression this year, but no one saw this coming. The common narrative goes that he has been lost at the plate since that Cubs series where they decided to walk him basically every single time he came up to bat. In actuality, the stats say that Harper's struggles this year are rooted in a steep decline in power.
Put plainly, Harper's just not hitting the ball as hard this year. According to statcast, in 2015, Harper's average exit velocity was 91.2 miles per hour. This year, that average has gone down almost two miles per hour, now sitting at 89.6. Below is a chart from 2015 that looks at his average exit velocity in each part of the strike zone.
While he did damage in most of the zone, Harper hit balls middle-low the hardest, averaging 101.8 miles per hour. Compare that to what he's averaging this season.
He's only averaging 96 miles per hour in the same spot this year, down over 5 miles per hour. He's also averaging five miles per hour less on his second strongest zone from last season, middle-away, and eleven miles per hour slower on pitches middle-up. While it's certainly possible that he's averaging less because he's not getting as many opportunities -- common sense says that he obviously wouldn't get as many good pitches to hit this year -- that's unfortunately not the case. Below is a breakdown of how Harper was pitched to in 2015.
And now, the breakdown from this season.
Basically, he's getting the same percentage of pitches to hit in all of the locations he hit best. Daren Willman, the brain behind statcast, gives an interesting insight into why that might be.
Bryce Harper's batted ball launch angle this year is noticeably higher compared to 2015. Especially ~ 20 degrees pic.twitter.com/k82lkW5R0B— Daren Willman (@darenw) July 21, 2016
Essentially, something in Harper's swing is causing him to get under the ball more often, causing what in 2015 were home runs to be fly balls in 2016. His batted ball numbers tell the same story.
He's hitting a much lower percentage of line drives and seeing a pretty sizeable uptick in fly balls. That doesn't translate into home runs, though, as his HR/FB rate is down 11%. He's also hitting the ball softly almost 11% more and hitting the ball hard 9% less. Interestingly enough, despite all his struggles, Harper is still putting up a better than league average season, sitting at a 115 wRC+ so far this year. The discussion all summer has been about how bad Harper's played and he's still having a season that's 15% better than league average; even when he's bad, he's good.