Orioles general manager Dan Duquette confirmed the news to MASN.
"We're trying to get our arms around it and it looks like surgery is indicated," Duquette said of the left-hander.
Britton, who was an All-Star in 2015 and 2016, led the league two seasons ago with 47 saves and had an 0.54 ERA and 0.836 WHIP.
The 29-year-old was slowed last season by two stints on the disabled list with a forearm strain before an MCL strain in his left knee ended his campaign. He was limited to just 38 games, registering just 15 saves while posting a 2.89 ERA and a 1.527 WHIP.
Britton was expected to be the subject of trade rumors since he will be a free agent at the conclusion of the 2019 season.