LAS VEGAS — It was the last night of the summer league in Utah, and R.J. Hunter was standing in a hallway talking about the differences from his first NBA season as he approaches his second.

Danny Ainge walked by, heard the conversation and piped in.

“The biggest difference is I wouldn’t be sitting out with a sore wrist,” Ainge said of the injury that flared again and put Hunter out of the last game of the Vegas league. “I have a left hand.”

It was suggested any Ainge sore wrist would be the product of shooting too much.

“You can tell him I took a charge every now and then, too,” Danny replied, continuing his roles of Celtics’ president of basketball operations and chief buster of chops.

“He was just busting on me, but he was telling the truth, too,” Hunter said. “Nobody wants to hear about a wrist in April and May.”

Hunter hopes to gather all the lessons he learned as a rookie and apply them toward a ticket to playing time. Just a year’s experience has made a major impact.

“That’s huge,” he said. “Working out before the draft is kind of just blind. You’re working out not knowing what you’ve got to work on. This summer’s been a lot of footwork and a lot of purposeful work. Last year, I did a lot of quantity. This year, it’s a lot more focused work and, I want to say, a lot of bang for my buck when I’m working out. Every single rep has to mean something. I’ve learned that, and I think that’s going to make me a lot better.”

The 6-foot-5 wing admits he didn’t fully grasp the NBA game when he got to the Celtics.

“No idea,” he said. “And there’s nothing that can really prepare you for it. You can watch all the film you want. You can compare yourself to other guys that are at your position. But you kind of have to go through it to really understand it.”

Now he’s in a position where the Celts need a consistent outside shooter — and he’s a shooter.

“I know what I can do,” Hunter said. “I know I can shoot. For me, it’s just getting on the court. All the other things — the defense and the details of the game — are what allow that to happen. So I have to take care of that part of the process. It’s definitely an adjustment, especially coming from my situation where I was a main scorer.”

Encouragement comes from even players like Kyle Korver and J.J. Redick needing time before becoming consistent contributors.

“I look at J.J. a lot, because it took him five or six years to actually be a consistent shooter in the league — and he’s an all-time shooter,” Hunter said. “So it’s all about patience. I think the first thing is believing in your abilities, and then just working on it.”

When he isn’t picking on Hunter, Ainge speaks of him in a more encouraging, though cautious, tone.

“He’s in the process of earning a spot in the rotation,” Ainge said. “We know he can shoot and we know he’s a good passer, and he’s fighting hard for an opportunity to play.

“But you’ve got to work to be good enough at the other elements of the game — defense, rebounding, strength. You can’t just be a shooter; you have to be able to do more. There are a lot of good shooters that aren’t in the NBA because they can’t do enough on the other end of the court.”

Hunter understands.

“It’s funny when I hear people tell me, ‘It’s a big year for you,’ ” he said. “Well, every year’s a big year.

“It kind of took me a year just to get (coach Brad Stevens’) trust. I think that’s most of it.”

Back in Utah, Hunter was just trying to hold up his end of the duel with Danny.

“He swears he played in the Stone Age,” Hunter said, “where it was like all warriors on the court and no fouls called ever.”

Ainge responded: “When’s the last time you played and somebody bit your finger?”

Hunter had never heard the story of Tree Rollins — and the famed “Tree bites man” Herald headline — though he said Rollins’ son played at his high school.

“They had a picture of my finger in his mouth. He nearly bit it off,” Ainge said. “We were fighting on the floor and got tangled up.”

“How did you feel about that?” Hunter asked.

“I felt sore . . . but I came out and (scored) 25 in the first half of the next game,” said Ainge, who actually had the 25 two games later. “They couldn’t stitch it, but I still played. Two hands, left and right. You can’t hold me down just because my wrist is sore.”

At that, Hunter surrendered, knowing Ainge was delivering a message. If it gets through, Hunter could be part of the answer to the Celtics’ need for a floor-spacing shooter.