Just 48 hours after winning a second straight Atlantic Division title, the Miami Heat are wondering what else can go wrong.

Alonzo Mourning was scheduled for surgery early today after fracturing his left cheekbone in the Heat's 121-95 victory over Boston on Tuesday night.Without Mourning, who averages 19.2 points and 9.7 rebounds, the Heat will have to make do with journeyman Duane Causwell and seldom-used Marty Conlon at center.

"We're going to have to step up without 'Zo," Heat guard Tim Hardaway said. "It's unfortunate. The big man is out for a while, but we can't concentrate on our injuries. We have to concentrate on winning and playing hard."

Causwell is averaging 8.5 minutes per game. His first starting assignment comes Thursday night against David Robinson and San Antonio.

"It's going to be a tough matchup," Causwell said. "I played against him when I was in Sacramento. He's like a guard - awfully quick."

Mourning and Celtics center Andrew DeClercq collided early in the third quarter, with Miami leading 72-50. The two players fell to the floor, but Mourning took the brunt of the collision, the side of his face hitting the top of DeClercq's head.

Mourning was taken to the locker room, where tests revealed the fracture.

DeClercq stayed in the game and finished with 12 points. Mourning also scored 12 points.

"I knew he was back there, but I didn't see him coming up," DeClercq said. "At the last second, I saw the white of his uniform. He caught me on the forehead. Both of us were going for the ball hard. I guess he got the worse end of the deal.

"I hope it heals quickly and that he gets back for the playoffs."