The Braves' starting rotation got many kudos this season for its top-notch performance, so it's easy to overlook the quality work of the 2009 bullpen, which was led by one of baseball's best relievers: Rafael Soriano. Among relievers with more than 50 innings pitched, Soriano ranked eighth in FIP, amassing a stunning 102 strikeouts in 75 2/3 innings for a rate of over 12 per nine innings. He's your classic, dominating fastball/slider closer, and his ice-cold mound demeanor is downright frightening. There isn't a whole lot of explanation needed to describe how overpowering he was, often making hitters look silly.
The question is what happens to him going forward, as he hits free agency for the first time this winter. It doesn't take more than a cursory look at the rest of the reliever FIP leaderboard to show that good relievers are often incredibly fungible: only two of the top ten are established "closers" (Jonathan Broxton and Heath Bell). Two were relatively unknown rookies (Luke Gregerson and Andrew Bailey). One was picked up off the scrap heap this winter on a minor-league contract (Kiko Calero). One was arguably baseball's worst closer in 2008 (Brian Wilson). One was traded this winter for a pair of nameless non-prospects (Mike Wuertz). Looking at that list, does it make sense to try to keep Soriano, or to try to find a hidden gem that might be just as effective for a fraction of the price? At the same time, though, Soriano really might be joining the ranks of Broxton and Bell as a guy that can truly be a shutdown closer for many years, and those are valuable commodities. And with Mike Gonzalez also potentially leaving, there isn't a whole lot of veteran stability at the back of the bullpen. Still, the specter of his injury-plagued 2008 looms large, and there were times in 2009 when it sounded like he was going through more nagging injuries (though he never missed substantial time), especially given Bobby Cox's egregious overuse of his top bullpen gun.
The Braves have always been famous for building bullpens on the cheap, and while I don't mind that strategy, I'm not sure I agree with the chatter that says the Braves will look to keep Mike Gonzalez while letting Soriano walk. Both Soriano and Gonzalez underwent surgery this winter, and both appear to be fully recovered. Unless the Braves have reason to worry about Soriano's health more than Gonzo's, I think Soriano's extra effectiveness (2.54 FIP to Gonzalez's 3.51) justifies his extra cost (Soriano will get a raise from $6.1 million, while Gonzalez only made $3.45 million last year). I'm not a fan of signing either to any kind of long-term deal, but in terms of offering arbitration, would it really be the worst thing in the world to get Soriano back for, say, $8 million instead of offering Gonzalez and taking him back for about $6 mill? Plus it seems less likely that Soriano would accept, given his increased shot at a long-term deal, and we'd get all the draft-pick compensation with none of the cash commitment.
The bottom line: Rafael Soriano's 2009 performance placed him firmly among the elite relievers in the game, and I think he'll be a very good closer for a long time if he can stay healthy. I can't see the Braves offering arbitration to both him and Mike Gonzalez, but of the two, I'd rather "get stuck with" Soriano than Gonzalez.