Tottenham boss Mauricio Pochettino has banished Andros Townsend from the first team after the player clashed with a club fitness coach on Monday at White Hart Lane.
The 24 year old has since been banned from first team training and will not be part of the squad for Thursday night's Europa League match at home to Anderlecht.
"He did not train with the group. He is not available to be selected tomorrow, he is not in the squad," Pochettino said.
"It's because of Monday. When you behave in the wrong way you always need to pay.
"It's always my decision when he is available again to be part of the squad.
"Discipline for me is very important. I can understand the player - we have a young squad and a player can make a mistake - but when you cross the limit it is important to stop that.
"As a manager I am very fair but the discipline is very important. The staff need to show respect to the player and the player needs to show respect to the staff."
Townsend has apologised for the spat but is believed to be considering his future at Spurs.
"Has he apologised? Yes, he recognised it was a mistake," Pochettino said.
"I can understand because I was a player and when you don't play you're unhappy and sometimes your expectation is bigger than the manager provides you.
"But it was not normal behaviour. He is young and you need to understand that it isn't the way to impress the manager.
"He needs to learn about football, about behaviour, about discipline, about a lot of things.
"Football is not only about taking the ball in your feet and playing. You have a responsibility as a professional."
Pochettino suggested the club have fined Townsend for the incident but insists the player can still have a future at White Hart Lane.
"All players have a future. It's up to them to have a future here. Football can change quick," Pochettino said.
"He is in the squad because we believe in him and believe he can give us very good things, but it is up to the player when he has the chance to impress me and show I am wrong in my decision.
"Has he been fined? It's a private matter. I think it's obvious. Your question and my answer."
