Left-hander Wade Miley, on his way to his best start since joining the Orioles, was removed from Sunday's game against the Tampa Bay Rays while making his warmup throws before the fifth inning with a muscle strain in his back.

He retired the first nine batters he faced and had thrown 67?pitches in four scoreless innings. The injury initially was called upper-back cramps but later clarified. Miley said he felt something tighten just below his left shoulder during the final at-bat of the fourth inning.

On a pitch to right fielder Steven Souza Jr., Miley seemed to overthrow and go to the ground on his follow-through. Catcher Caleb Joseph came to the mound to check on him and give him a moment to regroup.

“I slipped on a pitch, trying to go fastball, away,” Miley said. “I kind of lost my balance. I felt something grab in my shoulder blade area. It kind of stayed there and didn't go away, and in between innings, it kind of got a little worse. I felt it a little bit. I didn't think it was smart to stay out there.”

The early exit came in a much-needed strong start for Miley, who has been a disappointment since joining the team July 30 from the Seattle Mariners. He's made two quality starts in eight, and had an 8.41 ERA and a 1.87 WHIP in 351/3 innings.

Miley said it was tough to go out in the middle of what was shaping up to be his best appearance in seven weeks.

“Absolutely” frustrating, he said. “I thought I had some command on the fastball. My game plan going in was to be able to execute. It's just one of those things, I guess.”

“At this stage of the season, I'll take the four” innings, manager Buck Showalter said. “I'm hoping that he comes in tomorrow and feels good and is an option for us. I think we'll know a lot more tomorrow what we're dealing with.”

Mancini gets the call: First-base prospect Trey Mancini, one of the top hitters in the team's farm system, joined the Orioles on Sunday for his first major league call-up.

“It's a dream come true,” Mancini said before the game at Camden Yards. “It's the reason I've been playing baseball since I was 4 years old, was to one day make the major leagues. It hasn't all really hit me yet 'cause it all happened really fast. I found out yesterday evening, but I'm just trying to take it all in right now.”

Showalter said Mancini would be a right-handed-hitting asset off the bench for the final two weeks of the regular season, and should benefit from being with the team in such a high-stakes time.

Mancini hit .359 to win the Eastern League batting title at Double-A Bowie in 2015, and has hit .282 with 20 home runs and 26 doubles in 142 games between Bowie and Triple-A Norfolk this year.

With the minor league season over, Mancini had spent the month at the team's facility in Sarasota, Fla., staying active in case he was summoned.

Surgery pending for Pearce: To create a roster spot for Mancini, the Orioles placed infielder-outfielder Steve Pearce on the 60-day disabled list with a strained flexor mass in his right elbow. Showalter said Pearce was contemplating surgery.

“It's not Tommy John,” Showalter said. “It's different. This one is a four- to six-month rehab. He wants to be ready for spring training. I asked the same questions. It's not [Tommy John]. There's three little places, areas where he has got some tears. He wants to go in and repair as much as he can.”

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