BALTIMORE, SEPT. 18 -- The Boston Red Sox' recently faltering bid to win the American League East received a significant boost today when pitcher Roger Clemens threw for an impressive, apparently pain-free 20 minutes in the bullpen at Memorial Stadium and was returned to the starting rotation.

Manager Joe Morgan said Clemens will pitch Sunday against the New York Yankees -- pending approval by team physician Arthur Pappas, who will examine the right-hander Thursday.

Clemens, who is 20-6 with a 1.98 ERA, has not pitched in two weeks because of tendinitis in his right shoulder.

Plans originally called for him to pitch Friday if all went well this afternoon, but Morgan said he pushed the start back to assure Clemens will have a turn against the Toronto Blue Jays -- now tied with the Red Sox for first place -- the following weekend at Fenway Park.

"He's only going to get three more whacks, anyway," Morgan said. "So why not pitch him against the Toronto club? . . .

"He said he felt like he could've pitched today. The way he threw, I'd say so too."

Clemens threw 80 pitches to catcher John Marzano, and estimates were that most of the deliveries were in the upper 80-mph range. Clemens declined to talk to reporters, but Marzano said: "He looked great to me. I asked him if he felt okay, and he said he felt great.

"He had real good velocity, just as good as when I've caught him in games. He was pitching like he was throwing innings, and he struck out everyone he faced. . . . It's a good feeling to have your ace ready."

Clemens had won eight consecutive starts before losing to the Oakland Athletics in his last outing. He is a leading contender to win the Cy Young Award for the third time, and the Red Sox' hopes may rest on his wide-as-Texas shoulders.

"You don't like to say we can't win it without him," catcher Tony Pena said. "But we're a lot better off with him than without him."