While he was healing, Robert Williams studied Celtics’ schemes

The Celtics' Robert Williams, who returned from injury Saturday, said he was pleased that in workouts his burst returned quickly and that his lateral movement is back to where it was before he was slowed by hip pain. file/chris szagola/associated press/FR170982 AP via AP

Celtics center Robert Williams returned to face the Rockets on Saturday after being sidelined since Dec. 6 because of a hip bone edema.

Williams has been ramping up his activity in recent weeks and took part in all full shootarounds and workouts during Boston’s four-game Western Conference road trip. He underwent a final MRI after returning to Boston and was cleared to play.

He said he was pleased that his burst returned quickly and that his lateral movement is back to where it was before he was slowed by hip pain. But during his time out he was focused on improving his general understanding of the Celtics’ schemes.

He said Saturday his hoped that his “IQ change” was noticeable, and that he is determined to stop biting on bump fakes from opposing guards.

“Feel like just knowing my whereabouts on the court, me vocally, knowing that my voice can help people a lot,” Williams said. “Being a [center], obviously at the back of the offense most of the time, just speaking up. Recognizing what’s going on and making the right calls for other people.”

Williams said that Celtics guard Brad Wanamaker has been an invaluable resource during his absence. At halftime and after games, he routinely went up to Wanamaker and asked him to break down what was going right and wrong on the court.

Before he was hurt, Williams was averaging 3.9 points, 4.6 rebounds, and 1.1 blocks in 14.2 minutes per game. Brad Stevens said Williams’s playing time would likely be limited in the short-term, but he generally did not play big minutes anyway, so that should not be a factor.

“Obviously what makes him different is his vertical athleticism,” Stevens said. “He’s got a special ability in those small spaces to block shots, to go up and grab lobs, but he’s also improved passing the ball. I thought he got better in coverages and those types of things before he got hurt, and those are the things that . . . when the first guy comes at him full speed off a pick-and-roll, it’s not going to be like going against our coaches.”

Celtics guard Kemba Walker did some light running and shooting before Saturday’s game but did not play.BARRY CHIN/Globe Staff

Walker misses game

Celtics point guard Kemba Walker on Saturday missed his fifth consecutive game because of a sore left knee. Stevens said that Walker completed a workout on Saturday and will likely play some three-on-three on Sunday. If he is cleared for Monday’s practice, Stevens said, there is a chance he could play against the Nets on Tuesday.

Tatum on even keel

Jayson Tatum is generally unflappable, and it has been even more apparent during his dominant stretch over the past month. Stevens said that characteristic has always served him well, along with his ability to quickly pick up on concepts and alterations, perhaps even in the flow of a game.

“I always remember one of his first exhibition games, Charlotte ran a play that a lot of NBA teams run, and we had not gone through it in any way,” Stevens said. “He got burned on the first one. And on the second one he figured it out. And that’s why I think he has a chance to be really special, but he’d be the first to tell you he’s not finished and he can still get a lot better. Because he’s going to see all this new stuff.”

Celtics president Danny Ainge got together with former players Paul Pierce (left) and Kendrick Perkins during a timeout. BARRY CHIN/Globe Staff