Nathan's Replacement: Heath Bell?

This morning, Bob Nightengale of USA Today reported via Twitter that the Twins were heavily scouting Padres closer Heath Bell in anticipation of potential trade talks. Of course, Minnesota's interest in Bell isn't really surprising given that incumbent closer Joe Nathan is likely to be out all season with a torn ulnar collateral ligament.

Considering how much I enjoyed Sky Kalkman's piece on how Nathan's injury would affect the Twins' bullpen, I thought that I would take advantage of the nice spreadsheet he put together to see how much of an improvement Bell would be upon what the Twins already have. Kalkman's analysis is based around bullpen chaining, or the way in which bullpens are organized (i.e. the closer's replacement isn't a Triple-A replacement player, it's the set-up man, and so on through the bullpen..   almost like a chain).

Kalkman determined that the Twins would lose about 2.6 wins this season downgrading from Nathan to Jon Rauch in the closer spot, with the eventual "Joe Scrub" becoming the seventh man in the bullpen, a replacement level reliever. But what if the Padres trade for Bell, one of the better closers in the game, to replace Nathan? Or more exactly, to replace good ol' Joe Scrub.

Bell could certainly fit into Minnesota's payroll, he's only due $4M for 2010 and he's still under team control through 2011, so the Twins would have some insurance for 2011 as well if Nathan doesn't come back all the way immediately. The price in prospects would likely be noteworthy though, as the Orioles landed one of the better third base prospects in the game, Josh Bell, as part of the George Sherrill trade with the LA Dodgers. Sherrill had roughly 1.5 years of team control left, and is regarded similarly to Bell, although Bell's xFIP numbers have been consistently better.

But would it be worth it for Minnesota? How many wins would they gain from adding Bell? Well, I did the math (more like, Sky's spreadsheet did the math, but whatever). Approximating Bell to post a 3.00 ERA for next season, a reasonable expectation given what projection systems expect for him, and ERA's for the other pitchers in the bullpen, once again primarily utilizing projection systems to determine those numbers, and it would seem that Bell would actually make a pretty solid difference for Minnesota.

If the Twins were able to land Bell and make him closer, enabling them to return Rauch and Guerrier to set-up roles, with Jose Mijares, Jesse Crain, Clay Condrey and Brian Duensing taking over the sixth- and seventh-inning duties, they would only lose about 1.0 WAR compared to what they would otherwise have gotten with Nathan in the closer slot.

This is certainly a rough estimate, as the ERA's are simply projections and Leverage Indexes used were rough estimates as well, but from what I've seen this manner of evaluation is the best one out there for projecting the future performance of bullpens as a whole. But from what I've gathered, trading for Bell would net the Twins an additional 1.6 wins this season.

So while it's unclear exactly how serious Minnesota's interest in Bell is, and whether they've even talked to San Diego is still unknown, too, it would seem that taking a look at Bell would be worth Bill Smith and company's time. Because that's a pretty tight division, and roughly a win-and-a-half of value could make all the difference.