Red Sox trade Dan Butler to Nationals for pitcher Danny Rosenbaum

The Red Sox have traded catcher Dan Butler to the Washington Nationals in exchange for left-handed pitcher Daniel Rosenbaum.

Butler was designated for assignment by the Red Sox last week to make room for Craig Breslow on the 40-man roster, but really it was the acquisition of Ryan Hanigan that pushed the 28-year-old journeyman catcher out. With Hanigan and Christian Vazquez behind the plate in the majors, and Blake Swihart close behind in Triple-A, Butler's hopes of sneaking onto the major league roster as a backup had largely vanished.

As one would expect with a DFA situation, the return is not terribly exciting. Danny Rosenbaum is not a high profile arm, and at 27 has still yet to appear in the majors. He threw only 20 innins last year in Triple-A before undergoing Tommy John Surgery, but has at least had some success in the past, holding a 3.12 ERA over the course of six minor league seasons. In 2013, he pitched to a 3.87 ERA in 158 innings of work, striking out 102 and walking 67.

As it stands, the Pawtucket Red Sox don't really have any room for Rosenbaum in the rotation, with Matt Barnes, Brian Johnson, Henry Owens, Anthony Ranaudo, and Eduardo Rodriguez set to start. While recovery from surgery might delay the logjam, Rosenbaum is already throwing again. It will be interesting to see if he makes the move to the bullpen, or if the Red Sox have decided to pull the trigger on shifting, say, Ranaudo into a relief role in the hopes that he'll be ready to make a significant contribution to the major league bullpen without having to deal with the transition in the middle of the season.

Ultimately, though, the acquisition of Rosenbaum will likely be more of an excuse than an actual cause for any shifts in the Triple-A rotation. For pitchers just trying to earn a shot at the majors, Boston is probably the worst possible destination. Whether they're destined for the bullpen or rotation, there are a half-dozen strong arms in Triple-A just waiting for their time, leaving any new blood at the end of a long line.