The Boston Red Sox demoted Japanese right-hander Naoyuki Uwasawa back to Triple-A Worcester on Wednesday.
Boston removed the 30-year-old from its 26-man Major League Baseball roster to free up a spot for starting pitcher Nick Pivetta's return from the injured list.
Uwasawa made his MLB debut for the Red Sox on May 2 and pitched four innings of relief over two games, striking out three while allowing one run on two hits for a 2.25 ERA.
He was traded to Boston on March 27 by the Tampa Bay Rays, who initially signed him following his posting to the U.S. majors by the Pacific League's Nippon Ham Fighters.
Uwasawa may be recalled to Boston later this season if the Red Sox need to reinforce their bullpen, according to U.S. media.
