The Orioles selected Diplan's contract from Triple-A Norfolk on Sunday, Zachary Silver of MLB.com reports.
In order to open up space on the 40-man roster and 28-man active rosters for Diplan, the Orioles placed John Means (forearm) on the 60-day injured list and optioned Alexander Wells to Norfolk. Diplan will step into the bullpen as a replacement for Wells, who likely wouldn't have been available for the next couple of days after covering two innings out of the bullpen in Saturday's 5-2 loss to the Yankees. Expect Diplan to work mostly in lower-leverage or mop-up spots out of the bullpen while he's with the Orioles.