Manchester United coach Erik ten Hag confirmed Cristiano Ronaldo refused to come on as a substitute against Tottenham Hotspur on Wednesday and that he is now training away from the first-team squad.
Ronaldo was an unused substitute in Wednesday's 2-0 home win and walked down the tunnel with a few minutes of the match remaining after being left on the bench again by Ten Hag. The Portuguese striker was left out of the squad that will face Chelsea on Saturday.
"Yes," Ten Hag told reporters on Friday when asked if the 37-year-old had refused to come on.
"I am the manager, I am responsible for the culture here and I have to set standards and values and I have to control them. In the team, we have values and standards and I have to control that.
"It will (be) a (time for) reflection for him, but also for everyone else. Football is a team sport and you have to fulfil certain standards. And I have to control it."
Wednesday was not the first time Ronaldo has left the stadium early before a United match had finished this term, having departed ahead of the final whistle during a pre-season friendly against Rayo Vallecano.
Ten Hag insisted, however, it is not the end for Ronaldo at United.
"After Vallecano, I told him it was unacceptable... this is the second time, there are consequences. We miss him tomorrow.
"It's a miss for the squad but it's important for the attitude and mentality of the group and now we have to focus on Chelsea as that is important.
"The statement is also clear. He remains an important player in the squad."
The two sides meet at Stamford Bridge on Saturday as Chelsea, unbeaten in seven matches in all competitions under new coach Graham Potter, host a United side who have won four of their last five encounters.
Ten Hag confirmed Frenchman Anthony Martial will also be absent as he is still injured.