The St. Louis Cardinals have made it known they’d like to add a second left-hander to their bullpen for the 2013 season, and right now it appears free agent Sean Burnett is at the top of their list. Burnett, 30, would split the lefty specialist duties with incumbent St. Louis reliever Marc Rzepczynski, who had a down season in 2012 while handling the role largely by himself.
While Burnett did have an outstanding 2012 season (1.1 WAR, 2.79 FIP) and has always held left-handed hitters in check (.221/.291/.337) over the course of his career, he hasn’t exactly been consistent in terms of overall success, something that many relief pitchers struggle with. In the four seasons since 2009, Burnett has been worth over 1.0 WAR twice (2010, 2012) — and failed to reach even replacement level status in the other two years.
As mentioned, this alternation between bad seasons and good seasons is not especially uncommon for relievers, who often fail to clear even 50 innings of work in any given year. These small sample sizes frequently result in volatile statistics that prove general managers would be wise to examine carefully whether paying top dollar for a free agent reliever is really a wise decision.
A player with Burnett’s ability to silence left-handed bats is always useful in the majors, but given the fact that his main asset is specialist work, St. Louis (and any other team who looks to sign Burnett) will want to avoid committing too much in the way of financial resources to someone who may well prove to be an unsound investment.