The San Diego Padres have acquired outfielder Carlos Quentin from the Chicago White Sox for right-handed pitcher Simon Castro and lefty Pedro Hernandez.

Carlos Quentin, who has spent significant time in both outfield corners, enters his final year of arbitration. He’s estimated to make $7.5 million in 2012 before entering free agency in 2013, according to MLB Trade Rumors.

Quentin is above average with the bat, hitting .257/.352/.505 in four seasons in Chicago. In 483 plate appearances in 2011, Quentin hit .245/.340/.499 – numbers almost identical to his career line. Quentin has very good power and much of his on-base skills are due to extremely high hit-by-pitch totals (78 over the past four years).

He’s a solid offensive player, but he’ll leave hitter-friendly U.S. Cellular for Petco, and it’ll remain to be seen how his fly-ball-centric offense will adjust (Quentin has averaged near 50 percent fly balls over the past three years). Every hitter is hurt by Petco, but some adjust better than others .

Further hampering Quentin’s value is his defense. Over his career in the outfield, Quentin is -22 by DRS and -32 by UZR (-8 of that thanks to his arm rating), according to FanGraphs. His Fans Scouting Report numbers have also not been encouraging, with only one attribute (arm strength) being rated above average. Overall, he doesn’t appear to be a good outfielder.

At an expected $7-8 million in 2012, there isn’t a lot of value to be had here, especially on a team not expected to compete.

The Padres didn’t give up any top prospects, but they did give up a couple of intriguing pieces.

Prior to last season, Simon Castro was rated as the 58th best prospect in MLB by Baseball America. Kevin Goldstein had him pegged as the Padres second best prospect before ‘11.

Castro failed to build on his promising resume and when the Padres acquired a slew of shiny new prospects, he fell to Prospect Obscurity Land (outside of BA’s and BP’s top 10).

Check out his peripherals in Double-A from 2010 and 2011:

2010 129.7 20.2% 6.8% .271 3.34
2011 89.3 19.5% 4.3% .321 3.80

That looks like largely the same pitcher. His walk rate  actually went down, his strike out percentage went down only slightly, and his average on balls in play (of which he’d have the least control over) skyrocketed.

There are obviously some concerns. His groundball rate dropped (and his home run rate subsequently increased), his serious struggles in limited Triple-A innings are alarming, and the general decline in his strikeout rate as he climbs the ladder is not encouraging.

Still, if you’re telling me this guy was a legitimate prospect before last season and now he’s an afterthought, well, I’m not quite buying it. Either your prospect ratings weren’t that good to begin with, or you’re overreacting to his 2011 performance.

While losing Castro stings, Pedro Hernandez may be the bigger prize here. He’s left-handed, he doesn’t turn 23 until April, and he’s performed well at every level besides Triple-A. His career strikeout-to-walk ratio is 5.4. He’s K’ed eight per nine while walking just 1.5, in 343 minor league innings.

There are concerns, too, of course. His size, mainly, as he’s only 5-10, 200. Further, his stuff isn’t overpowering as his fastball sits in the high-80s.

Castro and Hernandez aren’t top prospects, and there’s a chance that they don’t develop any further. Still, why deal them for a one-year rental on a team not expected to make a true playoff push in 2012? Sure, they could deal Quentin at the deadline or pick up a draft pick or two next year if they decide to hold onto him (edit: probably won’t get picks, thanks to the new CBA).

Personally, I’d rather they held onto Casto and Hernandez or targeted someone with more long-term value than Carlos Quentin. This isn’t a terrible trade by any means and it doesn’t change my (still optimistic) outlook on Josh Byrnes, but I can’t say it gets my Fred McGriff stamp of endorsement.