The Tigers finally made a move to get themselves a new first basemen after watching Chris Shelton struggle mightily at the plate for three months straight. Sean Casey was swapped for minor league right-hander Brian Rogers.

Shelton torched opposing pitchers for a .324/.404/.783 line in April, but has hit only .260/.321/.370 with a homerun every 44 at-bats since then. His season line is still a solid looking .277/.343/.477 due to his early surge, but even that is below average at first base. What confuses me is that they add Sean Casey, who is hitting .296/.377/.408 for the season (although he is a much better hitter on the road this year, at .324/.406/.459) and in all honesty has done even less at the plate since April than the player he is replacing.:

• Month-by-Month Splits
• APR: .312/.353/.594; 32 AB
• MAY: .500/.571/.917; 12 AB
• JUN: .253/.349/.319; 91 AB
• JUL: .308/.389/.359; 78 AB

Zone Rating says that Shelton has been much better defensively than Sean Casey (.931 to .842). Casey also has -4 Fielding Runs Above Average so far, while Shelton has +7. The two players are not going to platoon at first either, as Shelton was optioned to Triple-A Toledo immediately following the trade. Let's take a look at their performances using positionally-adjusted Net Runs Above Average:

As you can see by the last column, there really is not that much difference between the two players production wise. My guess is that the Tigers feel Casey is a better bet to improve on his poor performance thus far due to his track record, while Shelton needs some time to figure himself out in the minors. There is not enough time left in the season for the negative difference to really cause much of a problem, and if Casey turns out worse than Shelton, it's not like they don't have the option of yanking him back out of Toledo. Shelton's EqA is also still somewhat inflated from his early season performance, although you could say the same about Sean Casey's first 50 at-bats or so. If the production wasn't so close, I'd think the Tigers were making a trade for the sake of looking like they were doing something.

Brian Rogers is a 24-year old pitcher in Double-A. He has done a fantastic job of shutting down the opposition so far:

Rogers has control and high strikeout rates, although his homerun rates combined with what appear to be very low Batting Averages on Balls in Play are mildly worrisome. Then again, he is allowing a .294 BABIP at home, and his stats don't seem to suffer for it. Rogers 2005 statistics were also impressive, although he was 23-years old in High-A ball. A nifty pickup in exchange for Sean Casey, whose value is really at a lull after many seasons where he was perceived much more highly than now. Take a look at his batted-ball stats for this year:

Rogers hasn't been allowing line drives often, and he's inducing a high number of infield flies. He has been giving up enough homeruns that I'd inclined to get nervous about his performance at higher levels, but there is certainly enough upside here to like the deal for Pittsburgh.

Now what does Pittsburgh do? Do they continue to reach for Ryan Shealy for first base, or do they finally let Craig Wilson play? I'm somewhat amazed Wilson hasn't been moved yet, but there are still a few hours before the deadline.