On April 29 in a start against the Mariners, Red Sox starter Daisuke Matsuzaka departed with stiffness in his elbow. It wasn't considered much of a problem and Matsuzaka remained on the roster, but in his most recent start on Monday night he walked seven Orioles in 4-1/3 innings, and Tuesday he was sent in for an MRI on his arm. Even before the results are in, the Red Sox are placing Matsuzaka on the disabled list on Wednesday.
Taking Matsuzaka's place on the roster will be 24-year-old righty prospect Michael Bowden, who has four walks and 28 strikeouts over 22-2/3 innings with AAA Pawtucket. Taking Matsuzaka's place in the rotation, meanwhile, will be Alfredo Aceves, who to date has appeared in 11 games as a long reliever. With Matsuzaka and John Lackey out, the Red Sox are down two-fifths of their starting rotation; although, if you want to look on the bright side, at least it's the worst two-fifths.