BOSTON -- As Celtics center Robert Williams sat on the bench with pain in his left knee during the third quarter of Boston's victory over the Minnesota Timberwolves last Sunday, he knew something was wrong.

But he also was terrified to know just how wrong it was.

"I was hurt ... I was so hurt, because I knew something wasn't right," Williams said Saturday during his first media availability since having surgery on his torn meniscus on Wednesday. "I could tell it was something that was gonna stop me from playing. So I really didn't even want to find out what it was at one point. Like, at one point, I was sitting on a bench, like the end of the third, and I knew something was wrong, but I was so scared to even stand up.

"But, thankfully, this is out the way and we on to rehab now."

The "this" Williams was referring to was the surgery he underwent -- a partial meniscectomy in his left knee after he injured the meniscus during Sunday's victory.

After Boston had torn through the NBA over the past two months, winning 24 of 28 games before Williams got hurt and outscoring opponents by over 16 points per 100 possessions during that stretch, his injury was a reminder of how fleeting runs like that in the NBA can be.

But after initial fears that it could cost Williams the rest of the regular season and playoffs, the four-to-six-week timetable for his return could allow Williams to be back on the court by the end of April -- in time for the second round of the Eastern Conference playoffs.

Williams said that he immediately felt relief in his knee after the surgery, and said he was happy that it proved to be the "best-case scenario" for his return.

"Because they told me that it was a good surgery," Williams said, when asked why it was the best-case scenario. "Everything went as well as we wanted it, as well as it could go, and their observation is that I can be back in that time frame.

"Just gotta take our time, make sure it's the right plan, make sure I'm healthy. This organization obviously cares about me long term more than anything. So just making sure it's the right plan and I'm ready to go."

This season has been a breakout campaign for Williams. Boston signed the 27th pick in the 2018 draft to a four-year, $52 million extension in the offseason largely on potential after he had played just a combined 113 games through his first three seasons. But Williams has emerged into a dominant force in the paint for the Celtics this season, averaging career highs of 10 points, 9.6 rebounds and 2.2 blocks per game in 29.6 minutes across 61 games. He has played a huge part in helping Boston become the league's best defensive team this season.

Now, though, the goal is getting Williams back on the court in the quickest fashion possible -- something he said he has complete faith in Boston's medical staff to do.

"This is not my first injury that I've been through with the Celtics organization, and I can just honestly wholeheartedly say, every time I got to enter their care, the expertise, them zoning in on my rehab has been great and it helped me come back numerous times," he said. "So I've got all the faith in the world in those guys."

And as for any concerns Williams won't be able to hit the ground running when he comes back? Williams said those are overblown.

"I mean, nah. S---, not on my part," he said with a laugh. "I mean, obviously, there's nothing that can compare to playing in an NBA game or obviously the playoffs, but just gotta get out there. Like riding a bike again. Get out there, get my wind under me, and I feel like I should be good, obviously, with the help of my teammates picking me up."