Liverpool manager Jurgen Klopp has claimed that Darwin Nunez was "provoked" before headbutting Joachim Andersen during Monday's 1-1 draw with Crystal Palace.
Nunez was sent off 57 minutes into his Anfield debut for throwing his forehead into the Palace defender's mouth and nose.
The Liverpool striker had done something similar moments earlier.
When the two players were jostling for position, Nunez appeared to throw his head backwards in the direction of Andersen's face.
Nunez missed with his first attempt, but not his second.
After the ball had gone out of play, Anderson charged up to Nunez and pushed him from behind. Seconds later, Andersen was on the floor.
Despite TV replays appearing to suggest that Nunez had been the aggressor, Klopp suggested that his player had been "provoked all the time".
Speaking to Sky Sports, Klopp said: "I have now seen it back. Of course that's a red card. He was provoked all the time but that's not how you should behave."
Asked how much Nunez had let his team down, Klopp replied: "Look, he knows that now himself.
"I will talk to him. It makes no sense for me to talk too much about it in public now.
"It was absolutely not the reaction you want to see.
"The challenge... the center-halves in the Premier League will do that to him. They want to have him. He is a handful himself, but yeah, that's not the [correct] reaction."
Nunez will now be banned for Liverpool's next three games.
Discussing how he intends to manage his striker during this absence, Klopp added: "I don't know exactly how long he will be suspended.
"But that is the situation, so we will use it for physical work. Not as a punishment, just to make him even stronger."
Liverpool were losing 1-0 when Nunez was sent off. But Luis Diaz scored a brilliant solo goal to cancel out Wilfried Zaha's first-half opener.