Britton said there are no plans to undergo an MRI. "They don't think that's something I need to do right now, which is always a good sign,'' he said after the Orioles beat the Toronto Blue Jays 11-4 on Sunday.
Showalter told reporters that Britton started to feel pain in his forearm after throwing a curveball on Friday, the same day he converted his 54th consecutive save opportunity. Britton's streak is tied for the second-longest in Major League Baseball history. Tom Gordon also saved 54 straight games. Former Dodgers closer Eric Gagne holds the MLB record with 84 consecutive converted saves.
The Orioles officially described Britton's injury as a left forearm strain when they announced the move. Right-hander Stefan Crichton was recalled from Triple-A Norfolk.
Showalter said it's too soon to tell whether Britton will be ready to return on April 26, the end of his 10-day stay on the disabled list.
"It's too soon to know, but we're confident it shouldn't be long term," Showalter told reporters.
Showalter said he planned to use setup man Brad Brach on Saturday if the Orioles had a save opportunity, but the manager will fill Britton's closer role on a situational basis. Mychal Givens and Darren O'Day also are options to close games.
"We have good options and we'll kind of play it accordingly," Showalter told reporters.
Britton, 29, leads the American League with five saves this season. The left-hander has a 1.29 ERA in seven innings pitched.
Information from The Associated Press was used in this report.