TAMPA, Fla. – Even Joe Torre wonders what he’ll see when Jason Giambi reports to spring training.

The Yankees opened camp yesterday, with pitchers and catchers due in town for the workouts tomorrow. Giambi, accused of using steroids and coming off 1 1/2 injury-filled seasons, isn’t due to arrive until Sunday, two days before the first full-squad workout.

“He’s my biggest question mark this spring,” the Yankees’ manager said. “We have to see what kind of player he is.”

By next week, Giambi will be examined as if a specimen under a microscope. Are his biceps smaller or larger? Is his swing faster or slower?

And most of all, is his power back? Or will he be baseball’s post-steroid era version of Superman zapped by Kryptonite, a shadow of the player who won the AL MVP award with Oakland in 2000 and convinced the Yankees to give him a $120 million, seven-year contract after the 2001 season?

“It’s going to be a tough emotional roller coaster for him,” Torre said. “And he’s had a tough go here the last year-and-a-half here anyway, last year with all the things that went on and the year before, when he had some problems knee-wise, where he couldn’t do some things. He’s lost confidence, in my opinion.”

Without the Giambi controversy, the first day of spring training would have been dominated by the Yankees trying to move on from their historic collapse last October, when they were within three outs of sweeping Boston in the ALCS before becoming the first major league team ever to lose a best-of-seven postseason series after leading 3-0.

But for now, steroids has pushed the never-ending Yankees-Red Sox fight to the back burner and overshadowed New York’s revamped starting rotation, which includes newcomers Randy Johnson, Carl Pavano, and Jaret Wright, along with holdovers Mike Mussina and Kevin Brown.

Giambi, 34, slumped to a .208 average with 12 homers and 40 RBI last season, slowed by an intestinal parasite and a benign tumor. At his news conference last week where he sidestepped questions about steroids but issued repeated general apologies, he talked about how hard he worked during the offseason to get back into shape.

Torre said Giambi looked far healthier than at the end of last season, when his swing was so ineffective that the Yankees dropped him from their playoff roster.

The Yankees thinks it is imperative that Giambi get off to a fast start, to show that he is the player he used to be. Giambi has a .288 career batting average and .507 slugging percentage in April, according to the Elias Sports Bureau. If he slumps early, the scrutiny will intensify.

“Then the thought process is going to be he couldn’t do this unless he – you know, in everybody’s mind he was on this stuff,” Torre said.