Jose Valverde

The upcoming class of free agents figures to present an interesting study in the way teams are evaluating relievers these days. After Albert Pujols and Prince Fielder, many of the most recognizable names are closers or relievers who have previously closed.

Modern analysis suggests it's foolish to invest heavily in relief pitchers due to their limited contributions and volatility in year-to-year production. But someone has to get those crucial late-inning outs, and the temptation for a team that thinks it's a contender to throw a lot of money at a guy who's coming off a year in which he posted a minuscule ERA or eye-popping strikeout rate is often too great.

Undoubtedly, suitors will use a variety of criteria to evaluate free-agent closers, one of which will be usage. Because usage can encompass so many things — innings, appearances, pitches, "high-stress" pitches, and so on — it's tough to say which is the most accurate reflection of a pitcher's workload; of course, this debate continues on for starters, too.

During the season, with the launch of CloserNews.com, we began keeping an eye on relievers who had pitched on three (and four) consecutive days, as that seems to be the breaking point for when most relievers must be rested. We've tallied that up here in a spreadsheet, along with a few other measures (standard and otherwise) of reliever usage, for the upcoming class of free-agent closers.

The objective here isn't to make any bold proclamations based on who threw the most innings; I may as well pen the inevitable mea culpa right now if it were. Rather, there are some interesting tidbits of note here, a few things to file away as these relievers ready themselves for free agency and teams prepare to bid.

• Heath Bell and Francisco Cordero were the only two of this group to pitch on four consecutive days in 2011. Bell is the only one to do it twice.
• Bell's abundance of pitches certainly seems to correspond with his dip in strikeout rate (7.32 K/9 in 2011 vs. 9.22 for career). Looks like he was having trouble putting away hitters, at least relative to his past performances.
• Francisco Rodriguez paced the group by pitching on three consecutive days six times. 
• Heavy usage is not unusual for K-Rod, though. He's pitched fewer than 65 innings only once in his nine full big league seasons, the red herring due to an off-field incident in 2010.
• Info was culled from Fangraphs and Baseball-Reference.