According to Gordon Edes of ESPN Boston, Daisuke Matsuzaka will miss a minimum of a month due to a sprained ulnar collateral tear ligament.
Matsuzaka had already dealing with issues of another kind -- He's been dreadful on the mound this year and this move, assuming he comes back healthy, would likely sideline him until after the All-Star Break.
Daisuke, also known as Dice-K, boasts a 49-30 record to go along with a 4.25 ERA. This season alone he sported a 5.30 ERA in eight outings. His best season came in 2008 where he went 18-3 with a 2.94 ERA.