Green is a restricted free agent next season, meaning, under the current collective bargaining agreement, the Celtics can match any offer made to the fourth-year swingman. They didn’t have such rights with Kendrick Perkins, who was an unrestricted free agent.

After a month in Boston, Green is getting accustomed to the atmosphere and appears comfortable enough to make a long-term commitment.

“First of all, I have a very longstanding friendship with Doc [Rivers] and Danny [Ainge],’’ Falk said after the Celtics beat the Knicks, 96-86, last night at Madison Square Garden. “You got a championship-caliber team, three Hall of Famers and [Rajon] Rondo really coming into his own.’’

The CBA expires June 30 and it’s unclear what rules will be in place when the Celtics and Green are allowed to negotiate.

“There’s a lot of uncertainty because no one knows what the rules are going to be, so I told [Green] I don’t want him to spend one nanosecond thinking about next year,’’ Falk said. “I want him thinking about how he can help the team be a factor in the playoffs. And I think he needs to take the next 30 games to get acclimated, learn the plays, get to know how the guys play and I think he can help them in the playoffs.’’

Falk said Green, who is averaging 11.2 points in 13 games, is a good fit in Boston.

“Jeff is a thinking-man’s player and Doc is a thinking-man’s coach,’’ he said. “He wasn’t looking for a new situation. He wasn’t asking to be traded. I think both players [Green and Perkins] were traded because of economics. He was drafted by Boston, a Big East guy, lives in Washington and he’s very excited, learning a lot and can’t ask for a better environment and win a title in his fourth year.

“Of course [he’d be interested in staying in Boston]. He’s in a great situation . . . He’s a Celtic kind of a guy. He just wants to win.’’

Rondo sprains pinkie Immediately after talking to reporters in New Orleans Saturday, Rondo had X-rays on his right pinky, which showed that it was sprained.

Rondo jammed the finger in the third quarter of the Celtics’ 89-85 win over the Hornets when he ran into Kevin Garnett on a screen under the basket. The finger went numb.

“I can’t shake hands,’’ he said, slapping hands instead. “Everybody tries to be a tough guy when they squeeze.’’

Rondo pointed to the side of his hand where the pinky meets the palm, describing where the injury was. He said in New Orleans that he had been playing with a jammed finger for about two weeks.

“This is probably the most pain it’s been, though,’’ Rondo said.

Rondo was 6 of 15 from the floor last night with 13 points and 12 assists.

Chemistry test LeBron James’s free agent soap opera dragged out over the summer, but Carmelo Anthony had the basketball world’s attention throughout the season before he ultimately landed in New York.

The frenzy didn’t bother Rivers.

“Carmelo’s a hell of a player,’’ he said. “It should draw a lot of attention, just like LeBron should have and did. I get that.’’

But even with another all-star in the mix, the Knicks have struggled since the deal (7-9 since the trade after last night’s loss) and there’s some concern about how long it takes superstars to jell.

“We just have to change things up a little bit . . . and figure out how we need to play to maximize everybody’s talents,’’ said Knicks coach Mike D’Antoni. “But I think the group’s good, there’s no reason or limit how good we can be, we’ve shown we can be pretty good. If we’re moving the ball, we’re fairly quick up and down the floor and we can get some good wins.’’

Anthony scored a team-high 22 points on 7-of-17 shooting last night.

Playing catch-up The Celtics clinched their division for the fourth straight year, and the rest of the teams in the Atlantic have made moves to close the talent gap in the hopes of also closing the gap in the standings.

Along with New York’s upgrades, the Nets added Deron Williams and the 76ers are much improved after hiring Doug Collins, a coach of the year candidate, to get a young core to come together.

Allen said he knows teams are trying to play catch-up after seeing the Celtics dominate the division for so long.

“Getting out of your division, you have to beat the top seed in your division, so you stack up against the favorites,’’ Allen said. “The last three, four years we’ve been the trend, so New York, they have to build up against us to try to compete. They’ve got to beat us.’’

Still, he said, whether the division becomes more competitive depends on how the moves translate on the court.

“I think it depends on really the numbers they put up,’’ Allen said. “Everybody looks good on paper. You could talk about them moving in the right direction in the summertime. But once the year starts, you can’t talk about it anymore, you’ve got to do it.’’

Changing it up Rivers played just three players off the bench against New Orleans, going with a playoff-like rotation. After trying to get reps for new players, he’s been selective about whom to play.

“I’m trying to get them minutes,’’ Rivers said before going 10 deep last night. “We’re going to need some of them. It doesn’t just take them out of rhythm, it takes the guys who’ve been here out of rhythm as well.’’