Celtics' Walker says stem cells 'calmed my knee down a lot'

Boston Celtics point guard Kemba Walker said Wednesday that his left knee has responded well to a stem cell injection that is expected to keep him out until at least January. ''It's definitely calmed my knee down a lot,'' Walker told reporters in a teleconference from the team's training camp. Walker missed a handful of games in February and then nearly had his first playoff run with Boston derailed when he tweaked the knee during workouts leading up to the resumption of the season in the bubble.