When Robert Williams got the ball in the post on a play during a victory over the Raptors last week, the Celtics’ center heard a loud voice from his sideline.

It was Joe Mazzulla.

“Score the (expletive) ball!” Williams said his coach yelled at him. “It just reassured me that we are going to need those things and my teammates do, too.”

As the playoffs begin this weekend, the Celtics are asking even more from their talented center. After missing the first 29 games of the season recovering from knee surgery and then several more games managing the knee in addition to a hamstring injury in March, Williams is ready to go and seemingly ramped up physically to begin the playoffs.

That’s obviously a big difference from last year at this time, when he missed the final seven regular-season games and then the first two games of the playoffs due to a torn meniscus.

“I’m feeling good physically,” Williams said. “I’m in a good mindset compared to last year, going through what I was going through. I’m just anxious.”

The Celtics were naturally cautious with Williams, one of their most important players who inspired last year’s turnaround and ensuing run to the NBA Finals. Now, after dealing with multiple injuries all season, he’s healthy at the right time and the Celtics seem pleased with how they managed him. He played 31 minutes and 25 minutes in last week’s two wins over the Raptors before sitting out the finale.

“I’m really encouraged he’s played the minutes he’s played in the last couple of games,” Celtics president of basketball operations Brad Stevens said on Sunday. “It’s such a balance as you get late in the year of getting appropriate rest and doing that through the minor injuries that everybody’s got, and ramping up and making sure that you play enough games at playoff minutes, making sure you have enough real practice sessions that challenge you. I think that’s really important.”

The Celtics need Williams in their pursuit of a championship, and they’re hoping he can impact both sides of the ball. Defensively, Williams is one of the best in the league, but he’s been challenged to grow his game offensively. The center has always been a willing passer, but with so many scorers around him, he’s needed some encouragement to be more aggressive.

“There are times we do need those easy two steals or two dunks a game to take pressure off our scorers,” Williams said.

“When Rob plays, when he’s a consistent threat at the rim, it just takes our team to a whole new level,” Al Horford added. “That last game we played against Toronto, I thought he was making an effort just to have an impact. And we know that he has that capability. And I’m excited to see him do that now in the postseason.”

Williams has always operated with a team-first mentality, whether it’s been coming off the bench this season or growing his game to what the team needs. At times, that’s required a push. But he’s embracing the challenge.

“(Mazzulla has) cussed me out more than once to score the ball,” Williams said. “We’ve all got to come together and reach the goal. …

“I love to accept the challenges and he can be honest with me. He can be honest with all of us as related to scoring the ball. Just things like that, man. And it lets me know he has confidence in me.”

ROOM FOR GROWTH: After some early season inconsistencies, the Celtics finished the season with a 110.6 defensive rating, second in the NBA behind the Cavaliers. They’re peaking at the right time, with the best defensive rating in the league over the last 15 games. But they’re certainly not satisfied.

“Even though the numbers say that we finished second, I actually do believe that there’s a lot of room for improvement for our group,” Horford said. “And I believe that we will do that. So I’m excited. It’s a challenge for us. But we definitely want to be better, defensively.”

The Celtics have had some of their best defensive efforts over the last few weeks and they’re hopeful that will continue into their first playoff series, especially after it carried them to the Finals last June.

“I feel like we never left it,” Williams said. “I feel like we always hung our hat on defense. It’s an easy effort, it’s a problem if you can’t give effort. It’s something we all expect out of each other. We’ve been making big steps on the offensive side of the ball and that’s great but you never try to downplay the defense.”

JAYLEN BROWN, who suffered a right finger laceration last week and missed the final two games, did not practice on Tuesday but is expected to do so Thursday or Friday before Saturday’s Game 1.

“It’s getting better,” Mazzulla said. “He wasn’t able to practice today but he was out there for everything. Still no restrictions, you know, heading into Game 1.”

Marcus Smart is also on track to be ready for Game 1 after missing the last three games with a neck injury. He practiced on Tuesday.

“He’s good. He’s ramped up,” Mazzulla said. “He was great today in practice, went live, he said he felt good, so he’ll be ready to go.”

ODDS-ON FAVORITE: The Celtics have opened up as the biggest betting favorites among all known first-round matchups to date, listing at -1000 series favorites against the Hawks, according to FanDuel Sportsbook.

Boston’s also favored to win the series in a short matchup overall in the seven-game series with the series spread being -2.5 games and the most likely series result bet being just five games (+160). The team’s title odds have dipped in recent weeks amid a fall behind the Bucks to the No. 2 seed in the Eastern Conference and their current odds of +360 to win the NBA title are a shift from the start of the season.