The Red Sox have exchanged left-handed pitchers with the Marlins, sending reliever Dustin Richardson to Florida in exchange for Andrew Miller. Marlins beat writer Juan C. Rodriguez seems to have fired the first tweet.
Miller, the sixth overall pick in the 2006 draft by the Detroit Tigers, was part of the Miguel Cabrera and Dontrelle Willis trade in late 2007. Since then, he's been plagued by injuries and control problems. Last year, he struggled in Double-A for the Marlins, putting up a 6.01 ERA in 85 innings, walking 61 while striking out only 66. He fared significantly worse in the majors, with an 8.54 ERA and a 28:26 K:BB ratio.
Richardson, fresh off of a breakout season in 2009, came into the year looking like a contender for a spot in the Red Sox' bullpen. While he would eventually get that shot, and posted a decent 4.15 ERA, his 14 walks in 13 innings were indicative of the walk issues he'd been facing in Triple-A.
Miller has primarily started during his career, making 54 starts in the majors. He features a low-90s fastball to go with a changeup and slider, neither of which has really proved to be a major league ready pitch-though the slider was grading out as a plus pitch when he was drafted.
It seems like this was a matter of potential for the Red Sox. While at 25 Miller is fast running out of time to prove himself, he's still a sixth overall pick, and a project for Curt Young to work on during spring training. Richardson wasn't likely to crack the bullpen out of spring training, and probably didn't have much beyond a middle/long relief ceiling. It's not a deal that's likely to pay off, but apparently the Sox thought a roll of the dice was worth giving up Richardson.