Yankees general manager Brian Cashman said Wednesday "it's too early to call" whether the rest program prescribed for Masahiro Tanaka's right elbow will work.
Masahiro Tanaka has been diagnosed with a partially torn ulnar collateral ligament.
Yankees placed RHP Masahiro Tanaka on the 15-day disabled list with right elbow inflammation.
The New York Post's George A. King III reports that Masahiro Tanaka has flown back to New York in order to undergo an MRI on his pitching arm.
Masahiro Tanaka uncharacteristically struggled on Tuesday, allowing five runs over 6 2/3 innings as the Yankees lost to the Indians.
Masahiro Tanaka allowed four runs for the first time in his career, but still got his 12th win as the Yankees defeated the Twins 7-4 on Thursday.
Masahiro Tanaka allowed just two runs over nine innings but took a loss Saturday against the Red Sox.
Masahiro Tanaka allowed three runs on six hits over seven innings to take his second loss of the season against the Orioles on Sunday.
Masahiro Tanaka improved to 11-1, allowing one run over six innings as the Yankees defeated the Blue Jays 3-1 on Tuesday.
Masahiro Tanaka struck out 11 while yielding two runs in his second complete game of the year to beat the Mariners 4-2 on Wednesday.
Masahiro Tanaka held the Athletics to one run over six innings as part of a 2-1 victory on Thursday afternoon.
Masahiro Tanaka struck out nine and allowed just an unearned run over eight innings in a 3-1 win over the Twins on Saturday.
Masahiro Tanaka allowed one run on five hits over 6 2/3 innings to earn the win against the White Sox on Sunday.
Masahiro Tanaka surrendered four runs -- three earned -- over six innings Tuesday in a loss to the Cubs.