BOWIE — With barking dogs providing the soundtrack and the Richmond Flying Squirrels providing the resistance, Orioles ace Chris Tillman made the biggest step in his rehabilitation from shoulder soreness Monday night in a start with the Double-A Bowie Baysox.

Just before hitting his allotted pitch count, Tillman completed 22/3 innings, striking out three with a walk and a run in on two hits, including a home run.

As his comeback progresses, Tillman said things are going well, but that he’s still learning a lot about his shoulder each time out, and little of that has to do with the game results.

“I felt pretty good,” Tillman said. “Pretty good. As of right now, I feel like it’s going well. It was just tough getting loose, but other than that, once I’m loose, I’m good to go.

“That’s all new for me. I’m kind of learning along with this process, as much as pretty much everyone is. I couldn’t tell you what’s normal or what’s not, but as far as I’m concerned, everything is normal so far. It was down in Florida and I’m sure it’ll be the same tomorrow.”

Tillman’s shoulder has been the dominant problem the club has dealt with, really, since spring training began. The injury, described as bursitis when it cropped up and cost him three weeks in August 2016, kept bothering him when it came time to start his offseason throwing program in December.

He had a platelet-rich plasma (PRP) injection in December, and the hope was an accelerated spring training schedule would get him back on the mound for the second week of the major league season.

Instead, as he was building his arm strength with bullpen sessions, the progress was halted. Tillman was supposed to have his last side session before debuting in a game March 12, but he never took it as he felt discomfort while warming up and was shut down.

He had a cortisone shot the next week, and has essentially restarted his progression since. Last week, Tillman pitched to batters in a live setting at extended spring training in Sarasota, Fla., then pitched two innings in an extended spring training game before returning north.

It looked early on that the former All-Star, even without his best stuff, would overwhelm the Double-A lineup sent out to face him. Tillman struck out the first batter he faced, former top prospect Slade Heathcott, on fastballs of 88, 88 and 87 mph. But the next, infielder Carlos Garcia, hit a hanging slider over the right-field wall for a home run.

Tillman regrouped with a groundout and another strikeout to end the inning, and worked his fastball up to 91 mph in that frame, but constantly sat 88-89 mph with the fastball throughout the outing.

That was enough for him to get through the day mostly unscathed. In a 1-2-3 second inning, he picked up his third strikeout of the day on a 90-mph fastball to catcher Matt Winn.

Early in the outing, and especially when compared with his starts last August when his shoulder was bothering him, Tillman had good command and was able to mix all four of his pitches — his fastball, curveball, slider and changeup — for strikes.

In the worst throes of last year’s shoulder discomfort, Tillman looked as if he was pushing the ball a bit and not following through. At least early, all his pitches had finish, and he followed through well.

His command escaped him a bit in the third inning, when he issued a one-out, four-pitch walk to the No. 9-hitter Rando Moreno, and a one-out single to Heathcott, before he got Garcia to line-drive out to right field on his 42nd and final pitch of the evening.

“I felt pretty good throughout,” Tillman said. “I feel like the first inning was probably my best inning, pitch-wise. Obviously, he put a pretty good swing on the ball, not a whole lot you can do about that. But pitch-wise, the first inning was pretty good.

“I kind of got sped up there in the third inning. I would like to do that one over again. There’s nothing wrong with that. You just want to go out and make pitches. I felt pretty good for the most part.”

His limit was 45 pitches or three innings, whichever came first, and Lucas Long cleaned up the third inning for him before Tillman made his way back to the home clubhouse.

The rest of his rehab schedule isn’t set in stone, but if the Orioles try and keep him at local affiliates, the next logical step would be Saturday at High-A Frederick. Neither Frederick nor Bowie is home for what would be his final affiliated start April 27, but Frederick is relatively local that day in Potomac, Va.

On a typical rehab schedule, Tillman would go four innings or 60 pitches in his next start, then get up to five innings and 75 pitches before possibly being available for activation.

The key until that date is to continue feeling good before and after his starts, and eliminate any mental obstacles regarding the shoulder, he said.

“There’s a lot of it that’s mental, I think,” Tillman said. “I think there is with any injury, regardless of what it is. I think that’s probably the most important part, getting past those mental hurdles. I feel like the physical part you can work through. I’m not saying I’m mentally weak or anything, but I think that’s a big part of it.”

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