Tillman is optimistic he'll be able to make his next start, though he was only able to throw 88 pitches before being removed.
"For the most part, I didn't feel it in my pitching delivery," said Tillman, who may have been pitching for a job with the impending return of Brian Matusz, who threw 60 pitches for Class A Frederick on Monday. "It was more to do with when I was breathing. It had nothing to do with the way my pitches felt or the pitch quality. My pitches felt good."
Tillman allowed five hits and three walks while striking out two in his first career start at Fenway Park.
"He has a lot of deception and they didn't center a lot of balls off him," manager Buck Showalter said. "He gave us a good chance to win; we just couldn't pitch those last four innings."
Showalter believes the 23-year-old pitcher will continue to have success if he can avoid long at-bats.
"That's a lot easier said than done," Showalter said. "I think he needs to take advantage of some of his counts. [Young pitchers] do it for spurts for two or three innings. It's pretty normal with young pitchers trusting their stuff and not giving the hitters too much credit."
Tillman has shown flashes of the pitcher the O's hope they have, like his six-inning, three-hit performance his last time out against the Mariners. But the former second-round Draft pick has a hard time stringing consecutive quality starts together, which he yet to do this year. He's also never won back-to-back games during his three-year career (32 starts).
"I think he's getting a better feel of what he needs to do to be successful and what makes him not successful," Showalter said. "I hope that continues. You're always looking for that consistency, and the more that they establish the track record, they're able to take some of the bumps along the way a little better."
Tillman's five scoreless innings Monday marked the sixth straight game in which Orioles starters allowed three runs or less, and they are 3-1 with a 1.47 ERA in that span.