In the midst of all this, though, two regularly contending AL teams -- the Minnesota Twins and Tampa Bay Rays -- saw their bullpen depth evaporate. Jon Rauch, Matt Guerrier and Jesse Crain all left Minnesota as free agents, while Rafael Soriano, Joaquin Benoit, Dan Wheeler and Grant Balfour are no longer Rays.
Stocking a pen with good relievers is actually less difficult than you might believe; the best skippers create roles that keep everyone sharp while employing all of their relievers in situations they can succeed in. Bud Black's effectiveness in exactly this department was a big part of the reason the San Diego Padres nearly won the NL West last season, and per BP's Adjusted Runs Prevented stat, measuring pen-wide effectiveness, San Diego's 88.9 ARP not only led the majors going away -- the second-ranked San Francisco Giants were more than 23 ARP behind, or the difference of nearly two wins above average relief work. (ARP works off average, not replacement level, so the standards are higher.)
The Twins (54.5 ARP) and Rays (47.9) rated among 2010's six best bullpens, but that was before this winter's defections. So what can they do to fill the void?