Most Tigers fans agree that the Edgar Renteria for Jair Jurrjens and Gorkys Hernandez deal has been a very bad one for the Tigers but let's forget about the deal and focus on Renteria for a moment. The Tigers need to decide what to do with him after the season as they have an $11 million team option for next season. If they decline the option there is a $3 million dollar buy out but, according to Cots Contracts, the Red Sox are responsible for that money. Given those parameters, I would say it's very likely that the Tigers will decline the option.
Declining the option would not necessarily mean that he is gone though. Instead of letting the option kick in, the Tigers could offer him arbitration. If he accepts arbitration, he would likely make less than $11 million and potentially a lot less than that. If he declines arbitration and another team signs him, then the Tigers would probably get two first round draft picks in the amateur draft. You can find more details at Detroit Tigers Thoughts. Another choice is to not offer him arbitration but still try to negotiate a contract. Of course, the final possibility would be to just let him go.
Is he worth bringing back if they can get the cost of the contract down to a more reasonable level? He's had a bad year at the plate batting .271/.323/.359. His .681 OPS ranks him 8th among 12 American League shortstops with 300 or more plate appearances. He has done better as of late though which suggests that he might be getting adjusted to the league. After batting a woeful .254/.301/.326 before the all-star break, he has batted .320/.386/.456 in 103 at bats since then. If he keeps swinging the bat as he has been recently, he could get close to his career averages of .290/.348/.404 by the end of the season.
How is his fielding? He looks a bit pudgy and slow for a shortstop but the numbers say he might not be quite as bad as he looks. The Fielding Bible system (reported by Bill James online) says that he has made 2 more plays in his zone than the average shortstop this year. They also back up my observation that he is better at going to his left (+7) than he is at going to his right (-5). He is 13th among 19 qualifying shortstops in the majors according to Zone Rating and is 13th out of 21 based on Revised Zone Rating. So, the consensus seems to be that he has been average to a little below average defensively this year which is the same as last year.
Based on the numbers and the fact that he is 33 years old, it would be nice to find another option. Ramon Santiago is having a good year in limited at bats but has a lifetime line of .238/.307/.318. I think he makes a good backup infielder but I don't think I'd want to see him as a starter. By all accounts, Michael Hollimon is more of a second basemen than a shortstop and there is no guarantee he'll be even as good as Renteria on a regular basis. Among free agents, Rafael Furcal is a solid player but he has a back problem and will likely be costly. Orlando Cabrera is a better fielder than Renteria but is 33 and not any better offensively. He'll also probably require a multi-year deal and they've got enough of those already. Cesar Izturis can field but can't hit. So their are other options but each has its problems.
I'm still torn on what they should do but, given all the alternatives, taking the arbitration risk on Renteria does not seem like a bad idea. He's not as awful as some have made him out to be and could bounce back a bit offensively in his second year in the league. There is also a real possibility that some team (especially a National League team) would take a chance on him and that the Tigers would end up with two draft picks. That would be a good result.