As the Red Sox search for relievers, one trade possibility would be bringing back David Aardsma, who played for the Sox in 2008.
According to Ken Rosenthal of Fox, the Mariners are looking to trade Aardsma rather than give him a raise from the $2.75 million he earned in 2010.
The righthander had a 3.44 ERA and a 1.168 WHIP. He was dominating in the second half (0.84 ERA, 0.938 WHIP). He has control issues (49 strikeouts, 25 walks in 49.2 innings last season) but every middle reliever has issues of some sort.