BOSTON (CBS) — Al Horford is getting better, but he will not be returning to the Celtics lineup Wednesday night when the Phoenix Suns come to Boston.

The Boston forward will miss his sixth straight game with a left knee injury, Celtics head coach Brad Stevens told reporters on Tuesday. Stevens added that Horford is feeling better, but he did not practice on Tuesday.

“It’s about him feeling good for the rest of the season, so he just needs to feel 100 percent as he goes out and goes through progression and drills and everything else,” noted Stevens. “We did not test him in anything that he failed, by any means. This is part of his progression. We knew he wasn’t going to play [Wednesday]. If we practice later in the week, there’s a chance that he’ll be able to practice, but I doubt we’ll be out there much now that we start playing every other day.”

The Celtics begin a stretch where they’ll play at least every other day until Jan. 23, playing 19 games in 36 days, so you can see why Stevens would like to get Horford as much time as possible to fully heal while he can.

Also limited in Tuesday’s practice was guard Jaylen Brown, who is questionable for Wednesday’s tilt with a bruised right hand. Stevens said the injury is “residual” from Brown’s nasty fall in Dallas back on Nov. 24.