BOSTON -- Celtics All-Star point guard Kemba Walker has been cleared to practice, the team announced Friday, and coach Brad Stevens says Walker's troublesome left knee has been pain-free for "over a month."

Walker's left knee has been an ongoing issue for Boston going back for a calendar year, to January 2020. In the weeks leading up to last year's All-Star Game, he was dealing with on-again, off-again discomfort in the knee. Then, after playing heavy minutes in the midseason showcase in Chicago, he struggled before the league shutdown in March because of COVID-19.

Then, when teams resumed practice in late June, Walker said he felt further discomfort in the knee, leading to the Celtics having him on a strict minutes limit during the team's seeding games inside the NBA's bubble at the Walt Disney World Resort in Orlando, Florida.

After an up-and-down postseason, with Walker initially looking great against the Philadelphia 76ers in the first round before running into more struggles against the Toronto Raptors and then the Miami Heat, he and the team agreed to have him go on a 12-week strengthening program to try to improve the long-term condition of that left knee in early October, as well as give him an injection into the knee.

Last month, the team said there would be an update on Walker's status during the first week of January. Now that there is one, the question will now shift to when Walker will be ready to make his season debut.

Stevens said he gave Walker credit for his willingness to take the time to get his knee right, rather than gutting it out and playing a level below what he's capable of instead. Walker has earned a reputation as someone willing to play through injuries, rarely sitting out at all during his first eight years in the league with the Charlotte Hornets.

"Credit to Kemba for saying, 'I gotta get this thing stronger, and I gotta make sure that it is ready to go through a season and then, if we're fortunate, a postseason,'" Stevens said. "But he and [strength coach Jace Delaney] have done a nice job putting together a plan of attack, along with Phil Coles, and then hopefully he'll be back soon.

"But we're not going to rush that. We'll see how the practice goes and all that other stuff."

Meanwhile, Boston is going to have to deal with a significantly depleted frontcourt rotation after center Robert Williams III tested positive for COVID-19, and fellow big men Grant Williams and Tristan Thompson were ruled out because of contact tracing under the league's Health and Safety Protocols.

That leaves Boston with just two available big men on their roster: starter Daniel Theis, and Tacko Fall, who is on a two-way contract.

"Well, obviously, we're going to be limited with the amount of guys that can play that spot. We'll basically have two bigs on our roster for the next couple of games," Stevens said. "It is what it is. I think the biggest concern for me is that when we're playing small at times, it's awfully small. And that's the challenge, right? We have to make sure that we mix and match as well as we can to keep as much of our wing depth on the floor, at least a couple of our wings on the floor, whenever we can."

Boston will, however, have veteran point guard Jeff Teague back, after he missed the past two games with a sprained ankle, as well as guard Javonte Green, who missed Boston's four-game road trip because of being placed in those health and safety protocols.

Stevens said that, while the team's depth is obviously taking a hit because of the protocols at the moment, he trusts what the league is doing and how it is handling the virus.

"The NBA goes through a incredibly detailed program whenever there are any concerns at all," Stevens said. "They basically relived the last few days, your time all together. And I know they do that with every team. It's a long, arduous task for our people that are in charge of all of our protocols and following all the protocols and for all the people at the league. Those people are putting in a lot of time and effort and they are the experts. I listen to them, and they tell me what we can and can't do.

Scott Brooks, who echoed Stevens' belief in the league to handle things the right way, added that Russell Westbrook, who dislocated a finger on his right hand late in Washington's loss in Philadelphia Wednesday, is "good to go" against the Celtics.