You have the best record in the league. You have weathered numerous storms all season, including injuries to key personnel and a frayed relationship between the coach and the star player.

	Theo Ratliff leads the league in blocks, and now will join his third NBA team.

So what do you do now? You make a change. A big change. The operative query at this point? Why?

There are generally two things you try not to do in the NBA when you make a deal: you try not to trade young for old and you try not to trade big for small. (The Wizards deftly managed to defy both of those adages in the Chris Webber and Rasheed Wallace deals.) The Philadelphia 76ers have violated the first, acquiring 34-year-old Dikembe Mutombo for 27-year-old Theo Ratliff. That is, of course, assuming Mutombo really is 34. Many think he's a lot older.

On the surface, this doesn't seem to make a whole lot of sense for the Sixers. Ratliff has been an integral part of the Sixers' success and the thinking that he may not be big enough, long enough, or intimidating enough to anchor a champion is ludicrous. He embodies everything that Larry Brown wants in a player: He's unselfish, he's defensive oriented, he doesn't gloat and he has been improving every year. You may recall, the coaches voted him on to the Eastern Conference All-Star Team. The commissioner selected Mutombo.

This is not to diss Deke. He does what he does. But he has never been on a team which has won a seven-game series, so it's not like the Sixers are getting someone who's been there. He doesn't have the offensive game that Ratliff has, although neither will be confused with Shaq. Sure, the Sixers may have kept Mutombo out of New York or Miami, but are they substantially better off now than they were yesterday?

From the outside, it doesn't appear that they are. They not only are giving up a younger, very good defensive center, but also someone who, given the opportunity, can actually put the ball in the basket. That someone is Toni Kukoc.

Why would the Sixers make such a dramatic change at this point in the season? Clearly, they are going for broke. Team president Pat Croce already is contemplating a ride into the sunset this summer on his Harley with a championship ring on his finger. He must feel that this is the way to do it. He had better be right.

But it's always risky to break up a successful team when you know that what you've got is, so far, pretty darn good. Yes, there is size in the West, but so what? That didn't seem to bother Philadelphia when it ripped the Lakers last week. And by the time Philadelphia gets to the Finals -- if it gets to the Finals -- Ratliff would in all probability have been playing and productive for weeks. (If I'm the Atlanta team doctor, I make sure that Ratliff is not damaged goods.)

There's also the delicate matter of chemistry here. Ratliff is one of coach Brown's favorites. He's under contract while Mutombo is a free agent-in-waiting. The Sixers run the risk of losing Mutombo in the summer and then what do they have? Maybe by then they won't care because they'll have a championship and still have Matt Geiger.

The Sixers also are giving up a proven playoff veteran who can score. Kukoc never seemed to fit into Brown's scheme, but we've seen what he can do and, Lord knows, the Sixers can ill afford to let a potential point-producer slip away. Kukoc was not averaging a lot of points or minutes, but he is someone you had to worry about.

Maybe the Sixers feel they're going to have to win every game 76-74. That may be the case if they're playing teams who are also offensively challenged, such as Miami or New York. But, at some point, they're going to need someone other than Allen Iverson to score. Could Kukoc have been that someone? We'll never know now.

The Sixers have rolled the dice and made a bold move. They've tinkered with a successful lineup and a successful scheme, which can be dangerous. Brown already has traded away Tim Thomas, Larry Hughes and Keith Van Horn, bypassed Paul Pierce in the 1998 NBA draft, and still lived to tell about it. He got a good player in Mutombo. He gave up a good, young player in Ratliff, an offensive threat in Kukoc (in a conference where simply being a threat is critical) and dabbled with his own good fortune.

That's just one reason why Sixers fans may be shaking their heads in the City of Brotherly Love. There could be more down the road.

Peter May, who covers the NBA for the Boston Globe, is a regular contributor to ESPN.com.