ATLANTA — The Celtics declared Al Horford out for Friday’s game at Atlanta (7:30 p.m., NBCSB) with a sore left knee, an injury he said has been bothering him for weeks.
Horford went to the locker room during Monday’s loss to the Hornets and returned, and then he was ruled questionable for Wednesday against the Knicks.
He played in that game, but the injury has not substantially improved, prompting coach Brad Stevens to hold Horford out of the first of a back-to-back set.
“I’ve been dealing with knee issues and we just thought it would be the best thing to do and get ready for Dallas,” Horford said. “It’s part of the season, it’s been a couple of weeks.
“We’ve gotten to a point where I don’t want to miss extended time, so we’re just staying ahead of it. It’s not concerning.”
Stevens said the club was activating rookie center Robert Williams as depth behind Aron Baynes and Daniel Theis. Williams has spent most of the season inactive or with G-League Maine but he has fared well in his limited playing time.