Yankees starting pitcher Masahiro Tanaka has been diagnosed with a partially torn UCL in his throwing elbow, according to New York general manager Brian Cashman.
Through eighteen starts and 129.1 innings, Masahiro Tanaka has been everything the Yankees hoped for when they signed him last off-season from the Rakuten Golden Eagles. With 9.39 strikeouts per nine innings and an ERA of 2.51, Tanaka has undoubtedly been the Yankees ace this season, and his efforts were rewarded with a selection to the All-Star game in his rookie year.
The Yankees will now be without Tanaka for at least six weeks, while he attempts to rehab the injury, though the likely outcome is that he will require surgery. If he does eventually opt for surgery, Tanaka will miss the rest of this season and is likely to miss most of next year as well.
Though the success rates of Tommy John surgery have escalated over the years, there are still no guarantees of regained form. That being said, you don't have to look very hard to find pitchers who are succeeding after repairing their UCLs; Stephen Strasburg and Adam Wainwright come immediately to mind, and Joakim Soria (though a reliever) has had a pair of surgeries, but is returning to the All-Star game this year and is having the best year of his career.
It is a blow to the Yankees' already dim playoff hopes. They currently sit in third place in the AL East, behind Baltimore and Toronto, but are fifth in the Wild Card race after the Angels, Mariners, Royals, and Blue Jays. Without Tanaka, they may just not have enough to carry them into the post-season.