(AP Photo/Alex Brandon)

Bryce Harper has been one of the most heralded prospects MLB has seen in some time. His debut earned him the 2012 NL rookie of the year after batting .270 with an .817 on base plus slugging and 4.5 wins above replacement and he has been mentioned in the same sentence as Mel Ott and Mickey Mantle. But since then, he’s been hampered by injuries and has largely been a non-factor this season.

To start, Harper is walking less and striking out more — while swinging at fewer pitches in the strike zone.

Harper plate discp

He is not hitting for any power, and while his batting average on balls in play is up (.360 BABIP vs. .306 BABIP  in 2013 and .310 BABIP  in 2012) the numbers suggest he may have lost some bat speed this season.

Harper has seen 203 pitches in excess of 90 mph this season and has put 38 in play while registering a swinging strike on 24. But as the velocity rises, he has more and more difficulty catching up.

2014 Harper bat speed

This is in stark contrast to seasons past, including last year where Harper suffered an injury after running into the outfield wall.

Harper bat speed

Harper has handled the mid level heat (92 to 94 mph) fairly well this season, at least in terms of making contact versus swinging strikes, but he hasn’t driven the ball with any authority. His isolated power (slugging percentage minus batting average) on pitches 92 to 94 mph is .250 this season, down from last year’s .300 mark. On pitches 95 mph and above it is .000.

He is also not hitting the ball as hard. Harper’s average batted ball distance on flyballs is much shorter this season (258.1 feet) than last year (292.3) or in 2012 (281.3).

Harper is missing on pitches inside, but also high and high and away, suggesting he might be guessing wrong on many pitches.

2014 swing and misses on pitches 90MPH and over (Source: Baseball Savant)
2014 swing and misses on pitches 90MPH and over
(Source: Baseball Savant)

Plate discipline has never been a big issue for Harper, so perhaps he is trying to compensate for a loss of bat speed, either because of injury or deteriorating ability. At just 21 years old it’s more likely his thumb injury is not fully healed, and perhaps more rest will help him get back on track.