The Harper Slump

There is quite a bit of speculation today on why Bryce Harper is in a slump. Jeff Sullivan notices that Bryce Harper’s slugging on fly balls returned to normal this year. It is the ultimate example of regression to the mean, as Harper was way above the mean last season, and right on the line this year. There is a catch:

Now, again, Harper’s air-ball exit velocity has dropped somewhat, and that’s of some concern. He hasn’t been hitting the ball exactly the same. But where last year he blew his expected production away, this year he’s where the numbers think he ought to be.

I suspect he was way above last year because he was hitting the ball harder. I ask, why isn’t he hitting the ball harder?

Jesse Spector looks at the PITCHf/x data for Harper.

According to PitchF/x data on Fangraphs, Harper has been worse this year against all pitches other than cutters and sinkers, but has particularly struggled with four-seam fastballs, sliders and curveballs.

Meanwhile, according to data from Brooks Baseball, pitchers are particularly focusing on that fastball weakness lately, with Harper seeing “hard” stuff 63.76 percent of the time in July — the highest rate thrown to him in a full month since April 2014. Harper’s average exit velocities on those pitches dropped to an average of 89.1 mph in July, only the second time in 10 months of tracking that he’s been below 90.

So Harper can’t catch up to the fastball. Again why? While Harper is considered in a three month slump, his May numbers were only a batting average slump. He walked a ton. Basically, pitchers stopped pitching to him. In June, his batting average came back, but without the power, and his OBP dropped some. Finally, since the start of July everything fell off the table.

My intuition is that Harper is hurt. He was hit by a pitch on the knee on May 30th. He didn’t play again until June 3rd. I suspect the knee was not quite ready when he came back, and that injury led to him changing his mechanics.

This great Washington Post story on Harper’s swing showedHarper’s tremendous weight shift from his left to right leg, as his left foot comes off the ground. Look at the video of Harper and the swing of Ken Griffey, Jr. at the link, and especially pay attention to the forces on Harper’s right knee compared to Griffey. Harper’s right knee shakes as he makes contact, while Griffey basically has a solid right leg. Look closely, Harper’s knee waves like a rubber band.

So Harper plays with a not quite healed knee, and when he swings it hurts. The natural thing to do is avoid the pain, so Harper changes his swing just a bit to put less pressure on the knee. That would be enough to make his contact weaker.

Prince Fielder was in a slump all year, and he needed neck surgery. Andrew McCutchen spent all year in a slump, and the Pirates are giving him a few days off. If I were the Nationals, I’d put Harper on the DL for two weeks, work on rehabilitating the knee, and let him come back healthier for the stretch run. With a decent lead in the NL East, now is the time to let him heal.

from baseballmusings.com http://ift.tt/2aGVbq2