He returned from the DL on Tuesday after spending time on the shelf with a left forearm strain and made two appearances before getting shut down Friday.
The southpaw underwent an MRI before the O's placed him back on the disabled list.
Britton, 29, has established himself as arguably the top closer in all of baseball. Coming into 2017, he had registered at least 35 saves in three straight seasons and converted all 47 of his save attempts in 2016.
Britton's 2017 season has been marked by injury, however. This latest issue is a major concern for the Orioles, as Britton is one of the team's most important pieces as it seeks a postseason berth.
The Orioles will have options with Britton sidelined, including Brad Brach and setup man Darren O’Day. While neither offers the consistency Britton has showcased in recent years, both are solid options for Baltimore until its star closer is able to return.