Celtic manager Ronny Deila has criticised Kris Commons after the midfielder launched a furious rant at staff for being substituted.
Commons, who scored the Hoops' goal in a 3-1 defeat at Molde in the Europa League's Group A, was seen shouting at Deila and his assistant John Collins after being taken off on 76 minutes on Thursday night.
"It is not acceptable. We are one team and it is not about one player. It was very disrespectful to every one of us," Deila said.
"He was talking to everybody. He was irritated he was taken off, and that's OK, but you do it a better way than he did it tonight.
"I have spoken to him. I can understand that players can be disappointed getting taken off but to show it that way is not how we want to have it at Celtic.
"The decision was a matter of having the balance between attacking and defending. There are a number of games coming up and Kris can be important in them as well."
The defeat left Celtic bottom of their group, without a win from their opening three games having drawn with both Ajax and Fenerbahce.
"It makes it much harder but we have two home games now. There is still a chance but we need to win against Molde and Ajax at home," Deila said.
"I am very disappointed. We didn't perform at the level we should do. We started OK and then they scored. We got stressed and were uncomfortable on the ball."