Bryce Harper is in a slump. Not a daily, weekly, or monthly slump, but a slump that has been going on since the beginning of May — nearly two months. Coming off a breakout season in 2015, Harper seemed poised to be even better this year. In April he had a .714 slugging percentage, a 1.121 OPS, and a 181 wRC+ (creates 81% more runs than the average hitter). No pitcher wanted to pitch to him. On a day during the first week of May, Harper went 0-0, with six walks and one hit-by-pitch. Since then, it seems like walking is the only thing he’s done well. In May, he hit .200/.363/.785 with a 105 wRC+. In June, he’s hit .262/.369/.720 with a 95 wRC+(though he did post OBPs of .422 and .351 in May and June, respectively). In essence, Harper has produced like an average major-league hitter over the last two months. The only problem with that is that Harper is widely regarded as not an average MLB hitter, but one of the best (if not the best) hitters in all of baseball.
Sure, hitters go into slumps all the time. It’s no reason to get worked up about a bad spell here and there. Remember, baseball is a game where a hitter fails 70% of the time and is considered a Hall-of-Famer. There are going to be 0-4 days.
But two months seems like an awfully long time. And it’s my job here to find out why. So let’s take a look.
The first thing that stands out when examining Harper under the microscope of a computer is his batting average on balls in play (BABIP). He’s hitting .257 in said category — well below his career average of .323 and well below the 2016 MLB average of .300. BABIP does reflect the ability of the hitter, but it also depends significantly on defense and luck. A batter whose BABIP is well below his career and league average may just be getting unlucky — whether that is from hitting the ball directly at defenders or defenders making spectacular plays.
So, is Harper hitting the ball with the same authority he did last year (which would confirm the idea that he’s getting unlucky)? Not quite. In the following table you can see that the number of line drives he’s hit (LD%) is down 7% and number of balls he’s hit softly (Soft%) is up 12%. He’s hitting fewer line drives and more fly balls (FB%) — but those fly balls aren’t turning into home runs, as his HR/FB% is down from 27% to 17% (i.e. last year for every 100 fly balls that Harper hit, 27 of those were home runs. This year he’s hitting 17 home runs for every 100 fly balls).
So, Harper is hitting more soft fly balls that are getting caught by outfielders, and fewer line drive that find gaps. Could this be a result of his discipline at the plate — his ability to differentiate strikes from balls and to swing accordingly? There are two things I want you to look at: Z-Swing% and O-Contact%. They sound confusing but they’re simple to understand. Z-Swing% is the percentage of strikes the batter swings at. O-Contact% is the percentage of balls outside the strike zone that the batter makes contact with.
You can see the difference between last year and this year. Harper is swinging at fewer strikes (5% less) and making contact with more balls outside the strike zone (5% more). That would explain why he’s hit more balls softly this year — he’s making weak contact with pitches outsize the zone. It’s much harder for a batter to hit a ball well outside the zone because it’s farther away from him. You can see the truth in this statement from the following graph (all qualified hitters from 2012-2016).
The graph shows the relationship between isolated power (ability to hit for extra bases) and O-Contact%. It’s pretty clear that the more often a batter makes contact with a ball out of the zone, the less likely that ball with result in a double, triple, or home run. In 2016, Harper is somewhere right smack in the middle of all the dots (0.65 O-Contact%, .225 ISO).
Before I end, I just want to make it clear that Harper isn’t by any means a bad player. He’s a superstar, an All-Star, and probably the face of MLB — oh, and he’s 23. But, for lack of a better term, he’s performed like an average player the majority of this season, so I set out to find why. I think it’s mostly due to being unlucky with his deflated BABIP, but I’d also be cognizant of plate discipline if I were him. Pitchers do try to pitch around hm — just being a little more patient and swinging at more strikes and fewer balls wouldn’t hurt.