Rockets star Tracy McGrady will miss three weeks because of back spasms, Coach Jeff Van Gundy said.

McGrady left practice on Friday after hurting his back on a layup. He did not attend the Rockets' game against New Orleans last night.

David Wesley replaced McGrady in the Rockets' starting lineup against the Hornets.

"Every team relies on greatness down the stretch," Van Gundy said. "However, I do believe that good teams can function efficiently with or without one player. Our chore to function without the one player is going to be tested."

The back spasms are the latest in a growing list of injuries that have slowed McGrady in the past few weeks.

The five-time all-star missed Houston's last two preseason games because of tendinitis in both knees. He bruised his left knee in a collision with Yao Ming in the practice before Wednesday's opener against Sacramento.