Cashner was placed on the 10-day disabled list Tuesday, retroactive to Saturday, after his Friday start against Toronto. With the O's off on Thursday and Monday, the hope is Cashner can throw a bullpen session this weekend and get back next week.
The righty said he had no history of back issues until the issue surfaced at Rogers Centre.
"It started before the game, and I tried to get it to work out, and I just couldn't get it to free up," he said. "I think as the game went on, I had no command, and I was just kind of grinding through it."
Cashner was originally slated to start on Wednesday against the Red Sox, but his injury forced the O's to make other plans. Yefry Ramirez was called up to make his first Major League start in Cashner's place. Lefty reliever Donnie Hart was optioned to Triple-A Norfolk to make room for Ramirez.
Ramirez notched six strikeouts and allowed three runs over 4 1/3 innings in his debut, a 5-1 loss to the Red Sox.
Orioles third baseman Tim Beckham will report to Double-A Bowie Friday as he continues recovery from surgery in April to fix the lingering groin discomfort that has plagued him over the past few years.
Beckham had core muscle surgery on both sides of his abdomen in late April to address the problem, and he was expected to miss six to seven weeks. Beckham is first eligible to come off the 60-day disabled list on June 23, and Showalter eyes that date as a real possibility for a return.
"I think he's going to make the 23rd," Showalter said. "It's been a long road for Tim. I think he's going to really find out a lot of the challenges he had that were related to the stuff that finally got repaired that he's had for quite a while. Even before we got him, it had been quite a challenge."
No. 1 Prospect Hays still in walking boot
Outfielder Austin Hays, the O's top prospect according to MLB Pipeline, will stay in a walking boot for two more weeks as he recovers from an ankle injury sustained in late May.
Hays last appeared in a game on May 24 and has slashed .224/.259/.374 with six home runs in 43 games for Bowie this year. He has also battled shoulder inflammation this year.
Zachary Silver is a reporter for MLB.com based in Baltimore.