Luciano Acosta, seen here against the Red Bulls on May 13, did not respond well to leaving last Friday’s match against the Philadelphia Union. (John McDonnell / The Washington Post)

D.C. United Coach Ben Olsen said he has cleared the air with Argentine attacker Luciano Acosta, who gestured and spoke back after being removed early in the second half of last week’s MLS match at Philadelphia.

Acosta, 21, was not fined or suspended.

“It’s been addressed, both individually and as a group,” Olsen said, “and I would be surprised if anything like that happens again.”

Acosta, on loan from Boca Juniors, was having perhaps his poorest performance of an otherwise promising debut season Friday when Olsen replaced him in the 61st minute. Acosta did not acknowledge substitute Julian Buescher entering the match and walked toward the bench.

He declined to shake Olsen’s hand and, when the coach said something to him, Acosta raised his right index finger and replied vocally. Olsen took a step toward him before Acosta sat down and the coach turned his attention back to the game, a 1-0 defeat at Talen Energy Stadium in Chester, Pa.

Afterward, Acosta said through an interpreter the commotion “wasn’t anything that serious because we were trying to say something to each other, but neither of us understood what we were saying.”

Acosta does not speak English, Olsen doesn’t speak Spanish.

“I don’t see it being an issue,” Olsen said Wednesday. “I’ve got pretty thick skin. I’ve been around, both as a player and coach, and I know how some things are because of one moment of emotion or other circumstances surrounding it that [the public and news media] aren’t privy to and what was actually seen and what was meant. I have a better idea of that. That stuff is between us and I don’t see it happening again.”

The issue was discussed by the team as a whole, as well.

Acosta is “a fiery guy who wanted to stay on the field, and Ben is not going to back down,” captain Bobby Boswell said. “It’s his team and he wants everyone to know that, and everyone does knows that. I don’t think it was that big of a deal; Ben addressed it and everyone understood it.”

On the broader topic of team unity amid a 3-5-4 start heading into Friday’s match at Kansas City, Boswell said he has talked to the group about such issues.

“It’s easy when you are winning and everyone’s in a good mood,” he said. “But when you are losing, you can’t start being a jerk to everyone. For me, that was my message: Why kind of person do you want to be? We have to respect each other and stick together to get out of these tough situations. It’s about getting back up when you get knocked down, not getting knocked down and pointing a finger or disrespecting each other and throwing each other under the bus. It was not a shot at [Acosta]; it was a message to the group.

“It’s about respect, and it’s highlighted when you have a guy who doesn’t respect the coach. It’s a big issue. If we are having respect issues in the locker room, it’s going to translate on the field.”

Acosta has started four consecutive matches since coming off the bench in five straight games.