"Jermaine O'Neal's recovery from knee surgery has taken a big step, according to Danny Ainge.

The Celtics president of basketball operations watched his recuperating center work out in Chicago yesterday morning, and later said that O'Neal's return to the team appears to be on schedule.

"It could be next week, which is about what we hoped for — the end of the month," Ainge said before last night's 90-87 loss to the Grizzlies. "He looks good. I watched him go through his workouts."

The most encouraging news, according to Ainge, is that O'Neal has been able to work out for approximately three weeks without swelling. In addition to working out with a trainer, the center has been playing one-on-one basketball.

"That's always the challenge," Ainge said. "He's been working out for that long without swelling, which is a big consideration."

O'Neal also lost approximately 12 pounds during his rehabilitation.

Ainge said O'Neal may join the team when it begins a road trip this weekend with back-to-back games in Indiana and Minnesota, though it's unlikely he would play."