I know, I know, fish in a barrel, but anyway, apparently Lynn Henning of the News thinks that Renteria is beginning to look like an utter liability at shortstop.
My understanding is that the Tigers signed him to improve on Guillen's performance, not to be Omar Vizquel, and in that respect, he has succeeded. You name it, Renteria's improved it: fielding percentage, range factor, zone rating, revised zone rating. A better criticism would have been to suggest that Renteria's performance at the plate has not been what the Tigers hoped to get from him.
Certainly, there's an argument that facing AL pitching will drop the average NLer's numbers, and Renteria is 33, not 23, so he's not likely to improve (nor even maintain, not necessarily), but nonetheless, Renteria's RC/27 is 3.48, below Sean Casey's 2007 level of 5.09 (remember, the idea was to put Renteria at SS so Guillen could play 1B with Cabrera coming in). Even Inge posted a 4.10 RC/27 last season, so hold off on commenting that Guillen is actually replacing Inge at 3B ...
Anyway, the biggest problem the Tigers have had is not defense at SS, but pitching, and Renteria isn't going to be taking the mound soon. If you're going to be criticizing an acquisition, it should be Willis (or maybe Jacque Jones, but of course he's already gone), not Renteria.