ALTHAM - The Celtics have played the Bulls and Magic three times. They're finished with the Suns and Jazz. Tonight, they play the Pistons for the first time - with the status of cocaptain Antoine Walker up in the air.

Walker sat out practice yesterday nursing a sore right knee. An MRI earlier in the day provided welcome news: There was no serious damage to the area. The knee is still sore, however, and coach Jim O'Brien said he's not counting on the durable Walker to be available tonight.