With Gerald Wallace going off on the Celtics for a second time this young season Friday night — “selfish” was the key adjective — new coach Brad Stevens was once again called upon to address discouraging words emanating from the locker room.

Wallace and Jeff Green first spoke up after a preseason defeat to the Timberwolves in Montreal, and the two, with Wallace in the lead, gave voice to the frustration of losing a 22-point lead and the home opener to Milwaukee.

Stevens didn’t really answer the question as to whether it bothered him or it was a positive that players were stepping up and speaking out.

“I haven’t read or seen anything of what they’ve said, so it wouldn’t be fair of me to address that specifically,” said Stevens before catching a flight to Detroit for tonight’s game against the Pistons. “But I do think that, at the end of the day, guys are going to often times say what they feel, and they are also in the heat of the moment.

“It’s a competitive game, and we were frustrated that we didn’t finish the game out yesterday. I didn’t see any ill effects of that today in practice, which was really good.”

Jared Sullinger, for one, wasn’t bugged by the remarks from his mates.

“That’s just our teammates speaking up and just seeing what they see,” he said. “You can’t really take anything personal. Once you start taking things personal, that’s when people fall apart. We understood what was said in the media. We’re just going to move forward from it as a team — not individually but as a team we’re going to move forward from it and understand that they’re just voicing their opinion. So hopefully it helps our team out.”

Wallace didn’t back away from his words yesterday, and Stevens, while not using the same harsh tones, did speak about the fact the Celts had just two assists in the second half while watching a seemingly easy win get away. The assist line was not a numerical fluke.

“That was real,” Stevens said. “I think the other thing is that the game will challenge you in a lot of ways mentally and emotionally, and we didn’t do a great job of just responding to runs. You can’t play in a 24-second shot clock . . . you can’t play timidly. You can’t play to hope the clock runs out. You’ve got to play through each possession. You can hold the ball maybe in the last minute if you’re up, but that’s about it. You’ve got to just play your game and play it as well as you can.