With Mike Trout going all Willie Mays on the American League and his precocious NL counterpart struggling, the Bryce Harper hype machine has died down considerably. Harper's OPS+ has dipped to exactly league average (100). That's still amazing for a 19-year-old -- just five teenagers in MLB history (Mel Ott, Tony Conigliaro, Johnny Lush, Ken Griffey Jr. and Edgar Renteria) have posted better batting marks while getting 400-plus plate appearances in a season. But Harper has undoubtedly been hampered by low stuff during his rookie year.
Here's Harper's contact rate by pitch location, and then the league average. He's connecting often on high and middle pitches. Stuff at the knees is another matter entirely:
Harper's contact rate by pitch location, 2012
Average contact rate by pitch location, 2012
Harper's miss rate on high pitches (17.3%) is much lower than the MLB average (21%). He whiffs more than most on middle pitches (15.6% versus the 12.9% average), but you'll see in a moment that he more than makes up for it with epic power.
On low pitches, however, Harper's 41.2% miss rate is far north of the 31.6% MLB average. And when he does make contact, it's rarely the kind of hellacious, seam-ripping hit we've come to expect:
Harper's slugging percentage by pitch location, 2012
Average slugging percentage by pitch location, 2012
He's slugging .444 against high pitches (.392 average) and a robust .604 against middle stuff (.481 average). Yet when pitchers pound him at the knees, Harper has been one of the worst in the game:
Lowest slugging percentage vs. low pitches, 2012
Opponents may be picking up on Harper's low-ball struggles: He has seen a season-high 47% of pitches thrown down in the zone this month (the MLB average is a little under 42%; Harper saw low pitches 41.4% of the time from April-July). There's little reason to think Washington's slugging wunderkind won't eventually figure out how to crush pitches thrown down. But in the meantime, going low is a winning strategy against Harper.