Per Ken Rosenthal of The Athletic, Britton is expected to be out for at least six months after suffering the injury while working out.
The left-handed Britton, 29, dealt with injuries throughout 2017, missing time earlier in the year due to left forearm issues and soreness. He was one of the top closers in baseball over the previous three seasons, registering at least 35 saves per year from 2014 to 2016 and putting up a 1.38 ERA in that span.
He was particularly superb in 2016, finishing 2-1 with a 0.54 ERA, 0.84 WHIP and 74 strikeouts in 67 innings, converting all 47 of his save attempts.
Brad Brach primarily served as the team's closer while Britton was injured, though Darren O'Day can also take on the role in a pinch. As Zach Kram of The Ringer wrote on the last occasion Britton missed time, however, it's the reverberations down the bullpen that could hurt the Orioles:
"Rather, it hurts most because of the domino effect it inspires, with Baltimore's lesser options being forced into the higher-profile innings subsequently vacated by Brach. Mychal Givens and O'Day are capable of assuming those duties, but they struggle against opposite-handed hitters, and the names further down the line who are slated to take their places — the Alec Ashers and Logan Verretts of the pen — are more erratic still.
It's a fair point and a major concern for Baltimore, especially as it looks to bounce back next season in the highly competitive AL East. The Orioles finished last year 75-87 due in large part to a starting rotation that ranked last in MLB with a 5.70 ERA.
That makes Britton particularly valuable to the bullpen, and his loss will have a profound impact on the rest of Baltimore's pitching staff.