The Rangers supposedly went hard after Bailey last year at the trade deadline, and as he's under team control through 2014, he provides an attractive counterpart to guys like Mike Adams and Koji Uehara, who are free agents after the season.
Rosenthal talks about other options, as well, and mentions that the Rangers are getting calls on Uehara, as well.
With the Rangers supposedly having prioritized Yu Darvish, and also having interest in Mark Buehrle, while talking about wanting to improve the bullpen, it makes me wonder if Alexi Ogando might not be headed back to the bullpen in 2012 if the Rangers sign Darvish or Buehrle or trade for a starter. While Ogando looked great early in the season, he was basically a two-pitch pitcher all year, and struggled after the All Star break. He may be a better fit in the bullpen, long-term.
As for Bailey, one of the interesting things in looking at his line is that his incredible 2009-10 seasons, when he posted sub-2 ERAs, featured miniscule BABIPs (.217 in 2009, .237 in 2010). While Bailey's ERA jumped above 3 in 2011, his FIP was pretty consistent in all three years. His xFIP was also pretty steady in all three seasons, but his career xFIP is significantly higher than his career FIP (3.40 v. 2.74, with a 2.07 career ERA), the product of a HR/FB rate that has stayed in the 5-6% range his entire career.