The Red Sox placed reliever Carson Smith on the 10-day disabled list on Tuesday with a right shoulder subluxation that president of baseball operations Dave Dombrowski said could be serious.
Smith allowed a home run to Oakland's Khris Davis on Monday and then injured himself throwing his glove in frustration. He has a history of shoulder issues and missed more than a year after signing in 2016 following Tommy John surgery on his right elbow.
"It's got the potential to be a major injury," Dombrowski told reporters at Fenway Park.
Smith has not emerged as a reliable eighth-inning arm this season, two years after undergoing Tommy John surgery. He's 1-1 with 3.77 ERA and 18 strikeouts in 18 appearances. He helped blow the opener in Tampa and in his latest appearance, Davis's homer gave the A's a two-run lead in the seventh en route to a 6-5 victory.
To replace Smith, the Red Sox recalled left-hander Bobby Poyner from Triple-A Pawtucket.
Shoulder subluxations run the gamut of severity, but some can lead to labrum issues and require surgery.
