BOSTON – Roger Clemens entered the visitor’s clubhouse at Fenway Park, looked down a row of cubicles to see Andy Pettitte in uniform talking to a couple of reporters and chuckled to Scott Brosius, “the lefty is still here.”

Thirteen hours remained until yesterday’s midnight trade deadline. But Joe Torre was prepared to begin a new rumor about Pettitte, that he would be starting tomorrow night for the Yankees against Toronto. What apt symmetry that the scheduled opponent is David Wells.

Because the biggest trade of this season is still the one the Yanks made in February of Wells for Clemens. Not any they contemplated this week involving Pettitte. Not the one they actually pulled off for that chatterbox World Series hero Jim Leyritz. And not any that went down elsewhere before the deadline, including the expected deal that would send Chuck Finley – whose official first name is now Yankee killer – from Anaheim to the Indians.

How the Clemens deal plays out is still the most pressing issue in the sport. Will he be the Roger Clemens of old or an old Roger Clemens? The answer only could determine if the Yankees repeat as champions or not.

He turns 37 Wednesday and hardly gave himself an early birthday present yesterday. Rather it turned into another day when the pre-game was filled with Roger-on-a-roll prognostications and ended with analysis of what is still wrong with him.

The Red Sox won 6-5 as Jason Grimsley actually blew what would have been a Clemens victory. But Clemens was hardly deserving in his first game at Fenway Park as a Yankee.

*He had as many wild pitches (2) as strikeouts.

*He gave away a lead for the 17th time this season, including four times in his last three starts.

*He was removed after allowing a leadoff single to Nomar Garciaparra in the sixth in what sure looked like a lack of faith by Torre, as if the manager were dealing with the currently tremulous Pettitte rather than one of the greatest pitchers ever.

Clemens had held Cleveland to one run in seven innings last Sunday. The hopeful Yankees had taken that as the latest sign The Rocket was ready to take off on one of his patented win streaks. “When Roger gets hot, he stays hot,” David Cone said before the game.

He got tepid in a hurry yesterday in his 193rd career Fenway start. He had been 3-0 here with a 1.64 ERA since infamously leaving the Red Sox. In his first time back as a Blue Jay on July 12, 1997, he struck out 16 Red Sox in eight innings and left with a defiant glare up toward Boston GM Dan Duquette’s box and begrudging cheers from the Fenway faithful.

Yesterday, the glares came from George Steinbrenner sitting next to the Yankee dugout. From the fans, Clemens merely heard boos before, during and after his performance as a Red Sox lineup that entered with a combined .170 average against him (13-for-76 with 23 strikeouts) put up four runs in five innings.

“I definitely think this is a showcase for him,” Torre had said of this start. “It’s a day game. On Saturday afternoon [nationally televised]. At Fenway. And his face is up there in a Yankee cap.”

Torre was making reference to a ring of painted faces around the Fenway middle deck of the players recently honored as the 100 greatest. Clemens was obtained on the first day of spring training because the Yanks believed he was not only one of the greatest, but still one of the greats.

It is hard to attach such recognition now to a pitcher with a 4.78 ERA and an inability to hold leads. Amazingly, Clemens has still yet to reach 100 strikeouts for the season (he has 98). If a playoff series started this week, Torre would have to put Clemens in a substantial role based on non-Yankee history.

And the Yanks need Clemens to be a playoff factor. Because they traded a substantial post-season performer in Wells. And because, even with Pettitte still in the Yankee plans, he is not yet in October designs.

The Yanks envisioned Clemens, Cone, Orlando Hernandez and Hideki Irabu providing cover so the Yanks could attempt to fix Pettitte without the pressures of fronting a rotation. The addition of Leyritz deepens the Yankee bench as should the ultimate arrival of Darryl Strawberry for his lefty might and Alfonso Soriano for his legs. Jeff Nelson should lengthen the bullpen when he returns from the DL and the Yanks will still eye a waiver trade in August for a lefty reliever.

But those are finishing touches. Clemens is a main figure. The Yankees need him to be a substantial contributor. Not along for the ride.