WALTHAM — Ron Adams remembers how opposing teams defended Rajon Rondo. Adams saw it when he was an assistant coach with the Bulls and elsewhere.
If there was any Celtic worth leaving open, it was probably Rondo. After all, shooting was more of a weakness than strength for the pass-first point guard.
“He was shooting better, from an opponent’s view point,” Adams said after practice Tuesday. “But like a lot of players, the technical part of his shooting, I thought, could be better.”
Then Adams joined the Celtics as an assistant, began working with Rondo this season, and now, Rondo has improved his shot, especially from 3-point range.
In fact, heading into Wednesday night’s game against Golden State, Rondo is shooting a career-best 36 percent from beyond the arc. And with his next 3-pointer, he’ll tie his career-high for makes in a season (17 in 2009-10).
“I gotta give Ron Adams a lot of credit,” Rondo said recently. “He’s been with me since Day 1.’’
Adams said Rondo deserved the bulk of the credit, but their work together began with a simple notion.
“One of the things we talked about was knowing when you’re open and shooting the ball,” Adams said. “That’s a fundamental change for him in some ways.”
They also examined every aspect of Rondo’s shooting motion.
“You start with the feet,” Adams said. “You see how fluid the shot is through the feet and then you work your way up.”
Then, there are Rondo’s large hands.
“That’s a little bit of an issue with him,” Adams said. “It’s good to have big hands, but he’s working on certain things as far as catching and so on so that he can catch and release and spin the ball in the right way.”
When it came to tweaking his shot, Rondo was a “good worker,” Adams said.
“He locks in,” Adams added. “He’s mentally tough.”
Adams said he’d like to see Rondo devote more time to working on his shot in practice, but Rondo is forced to spend a lot of time rehabbing his surgically repaired right knee.
But because Rondo is still working his way into form after missing nearly a year, his explosiveness isn’t quite there yet, which has affected him when it comes to his shots around the rim.
In fact, Rondo has made less than half of his 67 attempts from less than 5 feet of the rim. He is also just 3 of 21 on shots within 5-9 feet of the rim.
“Each game, he gets a little bit better, but I think he’s getting in an area where he’s close to the basket and he doesn’t have quite the snap that he once had on his drives,” Adams said.
“He was always clever at spinning the ball in and doing a lot of things; I think that’s coming back slowly. But that’s actually been a little bit more of a problematic thing for him than his jump shot has been.”
Celtics forward Jared Sullinger noted that on pick-and-rolls, opposing defenders used to go under the screen, allowing Rondo room to shoot.
“I see a lot of teams fighting over the top now because he will stop behind the 3-point line and shoot it,” Sullinger said. “He’s been hitting it this year and now teams are kind of worried.”
Coach Brad Stevens agreed and said he’s noticed that, in general, teams are defending Boston differently than they were at the beginning of the season.
Stevens also said it’s not a coincidence that their offense is better than it was two months ago “just because [Rondo is] getting more comfortable and he makes everybody else around him better.”
And Stevens went out of his way to praise Adams.
“Basketball coaches don’t specialize in one thing and ignore everything else,” Stevens said. “You have to be good at everything you do and he’s one of the best around and been noted as one of the best around. Defense, offense, individual instruction, whatever the case may be, he’s really, really good.”
Adams said he’s excited Rondo is seeing the possibilities of what his game can become and is working at his shot until it becomes more fluid and automatic.
“I’m not saying he’ll always have success, but it just becomes fluid,” Adams said. “It’s part of you. It’s part of your game. I think he’s seizing upon that at the moment, but I want him to keep spending more time and more time and more time on doing that.”
. . .
Swingman Gerald Wallace had surgeries on his left knee and left ankle Tuesday morning, the team announced. He will be out for the rest of the season . . . Forward Kelly Olynyk returned to practice after being sidelined for the past two games with a sprained big toe on his left foot. His status for Wednesday is unclear . . . Stevens said Avery Bradley should undergo an MRI Wednesday on his sprained right ankle, which has forced him to miss 14 of the past 17 games.Baxter Holmes can be reached at Baxter.Holmes@globe.com. Follow him on Twitter @BaxterHolmes