"First, we've got to manage the back, making sure that's something that we can resolve before there's a plan put in place," he said. "But, I think we should probably have something by the end of this homestand, what direction that's going to go."
Showalter said the main factor now is to see how he feels when the Orioles hit the road for an 11-game road trip to face the Boston Red Sox, Chicago White Sox and Tampa Bay Rays, beginning Thursday. Tillman, who lives in Sarasota, Fla., during the offseason, could rehab there.
Tillman had an MRI on Friday that revealed the lower back strain, Showalter said. He was placed on the disabled list a day after allowing six runs (five earned) while recording four outs in an eventual 11-6 win over the Kansas City Royals this past Thursday.
That outing left Tillman with a 10.46 ERA. He's struggled since a shoulder injury forced him to miss spring training in 2017, and hasn't found his form since.
Álvarez improving, not ready to start
Designated hitter Pedro Álvarez tested his hamstring with some light running and stretching in the outfield under the supervision of trainer Pat Wesley on Saturday morning, but there wasn't enough improvement to put him in the lineup, Showalter said.
"He moved around did some things," Showalter said. "I was actually waiting on the lineup to see if there was a difference. He's better today. I'm not going to elaborate on his availability today, but I'll leave it at that. I didn't think it was good enough to start today. I'm hoping that he's able to contribute soon."
Hess added as 26th man
Saturday's starter for the front half of the doubleheader, David Hess, was added as the extra man to the roster. Teams are allowed a 26th man for previously scheduled doubleheaders, and Hess' addition means he can't be sent down until after both games.
The Orioles can make a roster move after the first game that doesn't involve Hess. Saturday is the day outfielder Anthony Santander can be sent to the minors after satisfying his Rule 5 draft requirements.
Showalter said Hess will be given the opportunity to stay and claim Tillman's rotation spot with a good performance.
Around the horn
Showalter said infielder Engelb Vielma will have surgery Tuesday to repair a fractured patella, and a timeline for his return will be clearer by then. ... Showalter said left-hander Ryan O'Rourke, signed as a minor league free agent on his way back from Tommy John elbow reconstruction, has impressed in extended spring training. "He's 90-92 mph, throwing in games now," Showalter said. "He shouldn't be too far from going and joining a club somewhere." ... Outfielder Colby Rasmus (hip) is close to game action in Sarasota, Showalter said.