BOSTON, SEPT. 28 -- Only one thing is definite about Roger Clemens's scheduled start for the Boston Red Sox here Saturday: There definitely is no one who knows for certain whether he'll make it.

Clemens is listed as the Red Sox' starting pitcher for the second day of their three-game American League East showdown series with the Toronto Blue Jays, and his return from a 25-day absence due to severe tendinitis in his right shoulder is eagerly anticipated.

But there is considerable doubt about whether he will be able to pitch -- and some suspicion that Boston Manager Joe Morgan simply is playing mind games with the Blue Jays and has no intention of sending his ailing ace to the mound.

"Roger Clemens is my pitcher for" Saturday, Morgan said today, denying all allegations of a bluff. "At least I think he will be. . . . I hope. I don't know much more than anyone else at this point."

A scheduled start last Sunday in New York was postponed until today, then moved to Saturday when Clemens -- who's 20-6 with a 1.98 ERA -- could not throw at much beyond half-speed in a bullpen session last week.

"Only Roger knows for sure, so a lot is up to him," Morgan said. The Red Sox' plan is to warm up Clemens early Saturday afternoon, then decide shortly before the 3:20 p.m. game time whether to start him or left-hander Joe Hesketh.

Blue Jays Manager Cito Gaston said his greatest concern is that Morgan will send Clemens out for the pregame warmup, then switch to Hesketh with Toronto committed to a lineup of left-handed hitters.

"That would be kind of a breach of common courtesy," Gaston said, "but if Joe wants to do that, that's fine."