While baseball has certainly seen a market correction in recent years in terms of contracts given to relief pitchers, the signings of guys like Brandon Lyon, Fernando Rodney and John Grabow, whose mediocrity has been well established, to multi-year deals reflects that there's still work to be done in the evaluation of relievers. Now, this isn't another piece on how Wade, Reagins and Hendry messed up by committing so much cash to guys that are borderline fungible.

But it was signings like those that have caused by ask myself the following question many times this winter: Why haven't I heard Kiko Calero's name? I have hardly heard any speculation, any reports attaching him to any specific team. His name has been mentioned in passing on MLB Trade Rumors, attached to the Cubs and Giants, but he's attracted seemingly minimal interest thus far in the offseason. Sure, Calero hasn't been nearly as durable as Lyon or Grabow, but he made it through the 2009 season just fine (he missed a few weeks in June, his only DL trip), and there's considerable upside in a Calero signing considering that he's not particularly likely to get a multi-year deal or even close to the annual salary given to Grabow, Lyon or Rodney.

But we're talking about a healthy reliever with a career FIP of 3.29 and a career xFIP of 3.88, while posting respective marks of 2.56 and 3.92 over the course of 60 innings with the Florida Marlins last season. This is a pitcher who's been better than Lyon (4.40 career xFIP), Rodney (4.21), and Grabow (4.20) by a pretty sizable amount over the course of his career. But Calero hasn't even been in the same discussion as the aforementioned pitchers because he never got the late-inning opportunities that were granted to those pitchers, and his fastball sits in the 86-89 range, so he doesn't exactly look like the generic high-leverage reliever.

But when it comes down to it, Calero has easily been the most productive of these four pitchers since he entered the league in 2004. Since breaking into the league with St. Louis, Calero has consistently shown the ability to miss bats and avoid home runs, using a devastating low-80's slider to offset the lack of velocity on his fastball, which he throws less than half of the time.

According to FanGraphs' pitch values, Calero's slider was worth 8.9 runs in 2009, making it one of the ten most valuable sliders in the game among relief pitchers, in front of closers with famed sliders such as Carlos Marmol, Francisco Cordero, and Mike Gonzalez. While Calero's 2009 ERA and FIP marks were fueled by a .259 BABIP and a 1.4% HR/FB ratio, numbers that are highly likely to regress to his respective career marks of .286 and 6.7%,  he also posted big strikeout numbers, and there's little reason to believe that he won't continue to strike out over a batter per inning. 

Considering that Calero is clearly among the better relief pitchers in the game, why is there so little interest? CHONE, Bill James and other projection systems have Calero posting similar numbers to Lyon and superior numbers to Rodney and Grabow. The latter three got multi-year deals worth between $3.5M and $5.5M per season, while Calero seems destined to settle for one-year, $2M deal similar to the one that Joe Beimel signed for in the final weeks of last offseason.

While teams have certainly shown some clear improvement in their ability to evaluate and properly allocate payroll space relief pitchers, it seems that some relievers are still falling through the cracks. In a market that's been leaning towards the buyer's all winter, it appears that there are still some major bargains to be had. Even factoring in the injury risk, Calero seems to be at or near the top of that list.