Taj Gibson, who suffered a concussion on Saturday, didn't practice today and is listed as doubtful for Tuesday night's game against the Philadelphia 76ers.

"He's still not feeling great, so we held him out today," coach Tom Thibodeau said. "He's feeling better, but he still had some symptoms. We want to be cautious with it."

If Gibson doesn't play, either rookie Omer Asik or veteran Kurt Thomas will make the start at center.