Bryce Harper has done some pretty impressive things early in his major league career.
Not many players can say that they hit 42 home runs and posted an OPS higher than .830 over their first two big league seasons. Harper did that before turning 21, and he did it while spending the first month of his rookie season in the minors and then missing significant time in 2013 due to a knee injury.
Harper is a special talent. We know this.
That said, entering Harper's third season in the majors, there's still plenty of room for improvement. He'd readily admit that. And for the Nationals left fielder, the area that might need the most improvement is his approach against left-handed pitching.
Harper's career splits, like many left-handed hitters, show that he's far more effective when facing a right-handed hurler. Harper has hit an impressive .292/.373/.532 against righties in his career, compared to a .229/.312/.376 slash line against lefties.
That's a 217-point difference in OPS.
His walk rate isn't too different against righties and lefties; Harper averages one walk per 9.1 at-bats against right-handers and one walk per 10 at-bats against lefties. But look at Harper's power splits and you'll see some pretty dramatic differences in the numbers.
Harper has 34 career home runs in 643 at-bats against right-handed pitching (one homer every 19 at-bats), and just eight homers in 314 at-bats against left-handed pitching (one homer every 39 at-bats).
Check out this heat map compiled by ESPN Stats and Information (click on the image to enlarge it), and you get a visual sense of what the numbers above indicate. Harper has much better plate coverage against right-handed pitching, only really struggling with pitches down and away from him. Against lefties, Harper has issues with pitches on the entire outside third of the plate, as well as balls high in the zone.
Harper also sprays the ball around to all fields against right-handed pitching, while you can see by the home run chart in that link that only two of his eight career homers off lefties have been to center or left field.
Anyone who has watched Harper play a good bit over the last couple of years has seen him struggle with off-speed pitches thrown by lefties - particularly sliders - on the outside part of the plate. That's the most difficult pitch for most left-handed hitters to touch, of course, because it comes from a tough angle and sweeps across the plate. But Harper seems to bail out more than most, resulting in a lot of swings-and-misses and weak ground balls.
ESPN's research shows that Harper misses half of the sliders that he swings at from left-handed pitchers.
Interestingly enough, Harper actually fared slightly better against lefties in his rookie season than he did in his sophomore campaign. His slash line against southpaws was .214/.327/.321 last season, compared to .240/.300/.415 in 2012. His walk rate and on-base percentage did jump against lefties last year, showing that he was a bit more patient and not as likely to chase pitches, but the average and slugging percentage dipped.
Is that a reflection of the injuries that Harper battled last season that might've sapped his power to an extent? Possibly. But it's clear that if Harper can take the next step and improve against lefties this year, he'll be better off, especially in the late innings, when he tends to see an opposing team's top southpaw out of the bullpen.