Desmond Jennings was a key catalyst in sneaking the Rays into the playoffs last year, but carrying that success over to this year has not been easy. In 2011, Jennings finished with a .275/.374/.456 line, coupled with 10 home runs and 20 stolen bases in 26 attempts. However, as noted in this year's Baseball Prospectus, Jennings had a .1056 OPS in his first 23 games, but could only manage a .664 OPS in the final 40 games of his major league premiere.
Jennings has continued the latter trend in 2012, managing a nearly identical .667 OPS through 72 games this season. It's easy to view these numbers and assume that the real Desmond Jennings is the meager hitter who can't crack a .700 OPS, but the numbers suggest it's too early to make this assumption.
Jennings' ground-ball percentage has dipped 6.7 percent from last year. This is a trend that hurts someone like Jennings who possesses plus-speed and athleticism. The good news is that of that 6.7percent, 2.2 percent has resulted in more line drives. Meanwhile, the other 4.4 percent (his strikeout rate is nearly identical to last year's) has been made up in an increase in fly balls.
For someone who has average to sub-average power, this is not a good sign. It's even more alarming when you consider 16.3 percent of his at-bats have resulted in infield fly balls, a 6.9 percent increase from his infield fly-ball rate last year.
Essentially, Jennings is erasing his biggest tool, his speed, by putting the ball in the air. Even worse, he's putting the ball in the air in the infield at an alarming rate. But is all this a condemning sign for a second-year player? (Albeit, a 25-year-old player.) The problem seems to be a clear lack of plate discipline, and difficulty adjusting to the adjustments pitchers have made to him. Infield fly balls are the result of Jennings swinging and hitting balls he shouldn't be swinging at.
The second half of 2012 and the first half of 2013 will reveal if Jennings is destined to become your run of the mill third or fourth outfielder with speed, or something closer to a Carl Crawford archetype that the Rays hope he progresses into. I think some coaching and adjustments will push Jennings more towards his ceiling.
Again, there's some positives here: he's hitting more line drives, he's had more infield hits despite less ground balls and he's an extremely efficient base stealer, only being caught once in 18 attempts. Jennings' future is a matter of development, or a lack thereof. Both Jennings and the Rays need to ensure that that development continues.