Masahiro Tanaka has partially torn UCL, but no surgery yet

It's not the worst possible news for the New York Yankees, but it isn't good news, either: After getting an MRI and seeing the team doctor Thursday, right-hander Masahiro Tanaka was diagnosed with a partial tear of the UCL in his right elbow.

Yankees general manager Brian Cashman says Tanaka won't get surgery yet; instead, he'll rehab for six weeks and see if he can pitch. The injury could be similar to that sustained by Matt Harvey of the New York Mets, who considered rehab before deciding to undergo Tommy John elbow ligament replacement surgery. If Tanaka, 25, decides later on surgery, he'll miss the rest of this season and a good chunk of 2015 because of the 12-15 month rehab time expected.

Here's a glimpse into Harvey's thinking, via the beat writer for the Bergen (N.J.) County Record:

However, if the tear in Tanaka's elbow isn't as bad as Harvey's, if it's more like the one that Adam Wainwright of the St. Louis Cardinals sustained in 2011, a non-surgical course might work out for a while. Eventually, though, the ligament usually tears fully and surgery is required. At least 60 players, in the majors and minors, have gotten Tommy John surgery since Jan. 1 — a rate that leading physicians call an epidemic.

The New York Post reported first Wednesday that Tanaka was getting MRI on his elbow. An All-Star in his first season after coming from Japan as a free agent and signing for $155 million, Tanaka has performed better than most other pitchers in the majors. He dominated from April through June, but his past two starts yielded disappointing results — he allowed a combined nine runs and 19 hits — which also set off alarms.

Tanaka's numbers overall this season — 2.51 ERA with with 135 strikeouts in 129 1/3 innings — made him a leading candidate for AL Rookie of the Year and Cy Young. He's pitched a league-leading three complete games with one shutout. The Yankees have a 13-5 record in his starts.

New York already has lost CC Sabathia, Ivan Nova and Michael Pineda from their season-opening rotation. Nova also had Tommy John, and Sabathia might not pitch again this season because of a balky knee. Pineda's shoulder problems persist, though he might return in August.

Keeping Tanaka healthy probably is the only way the Yankees will continue to contend for the playoffs. Their record is 46-44 coming into Thursday. They're within three games of first place in the AL East, and in similar shape for the wild card.

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David Brown is an editor for Big League Stew on Yahoo Sports. Have a tip? Email him at rdbrown@yahoo-inc.com and follow him on Twitter!

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