Tanaka, who has battled elbow injuries over the past two years, is dealing with inflammation in his pitching shoulder, the Yankees said. In a corresponding move, New York recalled right-hander Giovanny Gallegos from Triple-A Scranton/Wilkes-Barre.
Yankees manager Joe Girardi said Saturday that Tanaka's shoulder shows no structural damage.
"We decided he needs a break,'' Girardi said.
The Yankees announced the roster moves before their game against the Boston Red Sox on Saturday afternoon, one day after placing left-hander CC Sabathia on the DL with a knee injury. New York also is without Michael Pineda, who will miss the rest of the season after undergoing Tommy John surgery on his elbow.
Tanaka, 28, last pitched Wednesday in a shaky performance against the Toronto Blue Jays. He walked a season-high five batters in four innings, but the Yankees won 11-5.
Tanaka said Saturday his shoulder felt sore and tired toward the end of the Blue Jays game. He added that he's frustrated to miss time but doesn't expect to be out long.
He was scheduled to pitch against the New York Mets on Monday. The Yankees have not named a replacement for Tanaka in the rotation.
Tanaka is 8-10 with a career-worst 4.92 ERA in 23 starts this season.