Adrian Gonzalez's power outage suggests further troubles for Matt Kemp

Adrian Gonzalez has hit three home runs this year, continuing a declining trend in his power output. (AP) On a sub-.500 Dodgers team that is struggling

Adrian Gonzalez has hit three home runs this year, continuing a declining trend in his power output. (AP)

On a sub-.500 Dodgers team that is struggling mightily to score runs, Adrian Gonzalez has been one of the few bright spots. However, his recent comments regarding the state of his surgically repaired right shoulder raise some doubt about his future productivity and sound an alarm with regards to teammate Matt Kemp, who's been slow to recover from a much more recent shoulder surgery.

Gonzalez is hitting .337/.398/.500 with three home runs in 113 plate appearances, certainly a respectable showing thus far. His on-base and slugging percentages both lead the team, which thanks to a slew of injuries has just five players who qualify for the batting title. His .343 True Average ranks fourth among qualified first basemen overall, and leads all NL ones.

For as productive as he's been, Gonzalez recently conceded that he's not the same kind of power hitter that he was prior to October 2010 shoulder surgery to repair a torn labrum in his right (non-throwing) shoulder. He told the Los Angeles Times' Bill Shakin that he's been unable to recover his old swing:

"I can still hit home runs… The full power is not the same.

…"Last year, I tried to go back to the swing I had before I got hurt… I tried it for the whole first half, with horrible results."

He said he is most effective now with a flatter swing that generates more line drives, rather than an upward swing that produces more power.

If Gonzalez is no longer the power hitter he once was, it's not entirely clear from his full-season statistics, which have been masked at least somewhat by the ballparks in which he's played. Take a closer look at his home-road splits, though:

Team	Yrs	Home PA	HR	AVG	OBP	SLG		Road PA	HR	AVG	OBP	SLG
Padres	2006-2010	1650	57	.267	.367	.442		1775	104	.307	.381	.579
Red Sox	2011-2012	636	18	.334	.388	.509		606	24	.308	.375	.518
Dodgers	2012-2013	141	2	.320	.362	.469		129	4	.304	.372	.461
Total		2427	77	.288	.372	.462		2510	132	.307	.379	.558

From 2006-2010, Gonzalez hit an impressive .288/.374/.514 and averaged 32 homers a year playing for the Padres, whose Petco Park was the most run-parched environment in the majors. Traded to the Red Sox in December 2010 despite undergoing surgery less than two months before, he had a strong enough season (.338/.410/.548 with 27 homers and an AL-best 213 hits) not to draw any complaints, and it wasn't even as though Fenway Park propped up his stats; his OPS was 57 points higher on the road, mostly due to slugging percentage.

Last year, he slipped to .299/.344/.463 with 18 homers during a season in which he started slowly (.283/.329/.416 with six homers through the first half) and was traded from the Red Sox to the Dodgers in late August. He homered in his first plate appearance with his new club on August 25, but hit just two more homers after that, both on Sept. 23.

Overall, the power outage has manifested itself most clearly in the decline of his road slugging percentage, which has fallen about 70 points since the surgery ( .579 to .508), masked by a 60-point rise in home slugging percentage (.442 to .502) that owes mostly to a higher batting average (.267 to .307).

Overall, it's fair to say that the shape of his production has changed. His .163 isolated power is his lowest since his rookie season, 50 points lower than his previous career mark, and one point lower than last year. His 8.0 percent unintentional walk rate is an improvement on last year's abysmal 5.4 percent, and right around his career mark. Meanwhile, his .345 batting average on balls in play is 21 points above his previous career high, but actually 12 points below his 2011-2012 output. If he can maintain this level, he'll still be an exceptional hitter, but if the hits stop falling in, his value will drop, and with five years still on his contract, he's got a long time for that to happen.

As for Kemp, after undergoing labrum surgery on his left (non-throwing) shoulder last October, he has yet to get back into the swing of things. He's hitting just .263/.323/.342 with one homer in 127 PA, and while he too has a .345 BABIP (seven points lower than his previous career mark) he's striking out in 24.4 percent of his plate appearances, a rate he has exceeded only in his 2006 rookie season and his subpar 2010 campaign.

Though both hitters had surgery on the labrums of their non-throwing shoulders, Gonzalez at least found a way to be productive in his first month back in action (.314/.378/.457), even after playing just 11 games in the spring. Kemp's injury, which he sustained while crashing into an outfield wall, may have been more severe. When he went under the knife in October, the hope was that he would need just a minor repair, but instead Dr. Neal ElAttrache needed to reattach his labrum to the socket. The injury required a longer rehabilitation than initially expected, and while he played 19 games this spring, his power was limited even then; it's possible he would have been better off taking things more slowly. At this point, he may not be able to come close to matching the 23 homers he hit last year in 106 games, let alone the 39 he hit in 161 games in 2011. How long his power outage will continue is no small concern given that he's got six years still remaining on his contract.

Hanley Ramirez