For the second straight offseason, the Red Sox underwent some bullpen remodeling in hopes of strengthening their overall pitching staff. This winter, Sox fans saw the additions of Andrew Bailey and Mark Melancon via trades, both of which coincided with the departure of flame-throwing Daniel Bard to the starting rotation. Last offseason, one of the bigger bullpen additions was supposed to be Bobby Jenks, who the Sox signed to a two-year, $12 million dollar deal in hopes that he would provide valuable depth as a lock-down seventh inning arm in front of Bard and Jonathan Papelbon.

As it turned out, Jenks was none of thee above. Due to an early season biceps strain in this throwing arm, followed by a serious back injury, Jenks only threw 15.2 innings with the Sox in 2011, finishing his first season with the team having allowed 11 earned runs in those few innings of work.

This past winter, Jenks underwent two back surgeries (spinal decompression, cranked up to 11) and will not start throwing until mid-March, barring any setbacks. His back has been an issue since the 2010 season, but he had managed to throw 52.2 innings that season while posting an inflated 4.44 ERA, but indicative 2.54 xFIP. The Sox saw a chance to buy low on Jenks, who had worn out his welcome on Chicago’s south side, and the $6M per season they gave him to be a setup man in Boston shows hom much they believed in his bounce-back potential.

Since breaking onto the big-league scene as a reliever back in 2005, Jenks has been had his share of ups and downs, but he has always been a consistent source of high groundball rates and low home runs rates (2009 aside). The season before he signed with the Sox he posted a 10.4 K/9 and 3.1 BB/9 while only allowing three home runs. However, his ERA suffered from an inflated BABIP (.345 compared to his career average of .301) and an extremely low strand rate (LOB%) of 65.4 percent (compared to his career average of 73.1 percent). All signs pointed to Jenks being an asset to the Sox’ pen, should he avoid a major injury. Of course, that scenario never came to fruition.

I’ve always been scared of players that have dealt with back injuries. There’s just no way to effectively play through that type of injury and it seems that back problems often haunt players even after they’ve been treated medically. The Sox obviously hope that this is not the case for Jenks in 2012, as he has the upside to turn most ballgames into a six inning affair should he return to form and become part of the bridge to Melancon and Bailey. At least he has reported to camp in good shape — his rather round physique has been a questionable part of his character throughout his career.

Until he takes the mound once again in game action, however, Jenks remains just another question mark in a long line of questions the Sox need to answer and answer correctly in order to survive in the brutally though AL East.