Left-hander Jason Vargas is on the Los Angeles Angels' 15-day disabled list after a blood clot was found in his left armpit.
The Angels also selected the contract of right-hander Billy Buckner from Triple-A Salt Lake on Friday.
The blood clot was discovered following Vargas' start against Seattle on Monday, making his move to the disabled list retroactive to Tuesday. He will seek a second opinion before considering surgery, the team says.
Vargas is 6-4 with a 3.65 ERA in his first season with the Angels, who acquired him from the Mariners in the offseason.
Buckner got his first major league victory since 2009 for the Angels last month, pitching five innings of two-hit ball in Kansas City. The 29-year-old hadn't pitched in the majors since 2010.