Bobby Jenks, Matt Thornton, and next year's closer

Bobby Jenks has closed games for the Sox since late 2005, but his run with the Sox may end in the offseason. (AP)

Bobby Jenks may have pitched his last game in a White Sox uniform Tuesday night.

A freak calf injury has ended Jenks' season, and given that he's due a healthy raise in the offseason, he's probably the most likely member of the current Sox team to be dealt over the winter. With that in mind, there are a few simple things that need to be taken into account regarding a possible Jenks trade.

Pros:

1. It'll likely save the Sox money. Jenks was awarded a then-record $5.6 million arbitration settlement last winter (that record was quickly broken by Jonathan Papelbon's settlement a few days later), and he'll likely make $7 million or so in arbitration this winter. If the Sox were to trade Jenks and slide Matt Thornton ($2.25 million club option for 2010) into the closer role, those are some pretty good savings. The only way it wouldn't save the Sox money is if they spent the $4-5 million on a left-handed setup man. Even then, though, the net gain of trading Jenks and signing a good lefty reliever would probably be worth it.
2. The Sox could theoretically get a decent return for Jenks. I'm not going to speculate on the players that return could be, but I'd have to guess the Sox would first try to acquire a major league outfielder. However, if the market trends toward less expensive contract for closers again, teams may see free agents like Fernando Rodney, Rafael Soriano, Jose Valverde, or Mike Gonzalez as better options. If that's the case, then the Sox might not be able to get a decent return for Jenks.
3. The Sox won't be allocating a lot of money to a position that doesn't require it. It's really not hard to find a cheap closer who could duplicate Jenks' 29 saves with six blown saves. I'm not a huge believer in throwing money at closers because they're generally easy to replace with a setup man or minor leaguer. That doesn't mean I'm against signing closers, but if you're a team that doesn't have a whole lot of cash to throw around, you're probably better off using a former setup man than signing, say, Brian Fuentes. That being said, you don't want to be like the 2008 Cardinals and have something like 35 blown saves as a team. There's a happy medium there, and I think the Sox have it with Thornton.

Cons:

1. It would leave the Sox with an inexperienced closer. Yes, Matt Thornton doesn't have extensive closing experience. But as Jim at Sox Machine noted, Thornton's leverage index has been the same as Jenks. Simply put, Thornton has pitched in similar pressure-packed situations in the seventh or eighth as Jenks has in the ninth. However, that's not necessarily an indication that Thornton will succeed in a closer's role. It's not unprecedented for a setup-man-turned-closer to fail in that new role, but then again, a lot of those setup men end up being pretty good closers. The only way to know is to try out Thornton as a closer and see if he does well. I think he's earned that chance at this point, though.
2. If Thornton replaces Jenks as a closer, the Sox would need to get a lefty reliever. The market for left-handed relief pitchers is pretty weak this year, with Joe Beimel and John Grabow being the best options. Picking up a left-handed reliever on the trade market won't be easy, either. If Thornton is moved out of his current role, there's almost no chance the Sox will find a lefty who will be as effective as Thornton in that role. I think it's fair to say Thornton has been one of, if not the, best left-handed setup men in baseball over the last two seasons, so replacing him would be next to impossible.
3. If Thornton isn't moved to the closer role, the Sox would need to acquire a closer. The Sox would have to go cheaper than Jenks to make trading him away worth it. This likely would eliminate most free agents—although if the Sox wait for the top-line closers to sign, they could pick up somebody for cheap (my personal favorite is Mike Gonzalez, who is dominant but does come with a little injury baggage. Still, I'd expect him to be sign a pretty nice deal at some point over the winter). The Sox could make a trade to get a closer, but that could cost them valuable minor leaguers or whoever they get in return for Jenks. If the Sox do go the trade route, they probably would try to pluck a projectable, under-the-radar middle reliever or setup man off another team's roster for cheap. Doing so, however, would not be easy.

My take is that the Sox should seriously consider trading Jenks, but they need to make sure that they can bring in somebody to either replace Jenks or Thornton as a lefty setup man. The worst thing the Sox could do is trade Jenks, move Thornton to the closer role, but not adequately fill Thornton's spot in a bullpen. The Sox' 2010 bullpen has the potential to be the team's Achilles' heel (along with defense), especially if Tony Pena doesn't figure out how to be a consistently effective reliever again.

Trading Jenks has the potential to deplete the Sox' bullpen depth, but then again, keeping him may not be cost-effective. In theory, what the Sox should do is sign a left-handed reliever and then try to trade Jenks, but that strategy could present a few problems.

First, if the Sox act quickly, they probably would end up overpaying for that lefty reliever. I'd hope the Sox learned their lesson in overpaying for relievers with Scott Linebrink, and giving anything more than two years to Beimel or Grabow would be pretty risky given the fickle nature of relievers.

However, if the Sox wait to trade Jenks, they might miss out on signing one of the left-handed relievers on the market. If that's the case, then the Sox probably wouldn't end up trading Jenks unless the team is extremely desperate to cut payroll.

Or, if they wait, they could end up signing a left-handed reliever but not being able to trade Jenks because all the teams that were interested already filled their closer vacancies. That's not entirely a bad thing—it'd give the Sox some nice bullpen depth—but again, if the Sox need to save money, it won't work out well.

The whole money issue is the main reason why the Sox would consider trading Jenks. You can argue that Jenks is already on the downslope of his closing career and the Sox would be smart to trade him now, but I don't think that's what the Sox are thinking. Unless Jenks was one of baseball's five most dominant closers, I think the team would consider dealing him in the offseason regardless. It's all about saving money and/or using that money elsewhere (Bobby Abreu, maybe).

To be honest, I don't know how to end this article. Should the Sox trade Jenks? Short story yes, long story maybe. There are just so many factors that will effect Jenks' trade value to the Sox and other teams. 

As you can see, this is a pretty complicated issue for the Sox. I'm just glad I'm not the one making the decisions.