Manchester United manager Louis Van Gaal accused Marouane Fellaini of "unbelievable stupidity" after being sent off against Hull City on the final day of the 2014-15 Premier League season.
Fellaini, 27, was dismissed for a reckless foul on Hull defender Paul McShane during Sunday's 0-0 draw at the KC Stadium, and is set for a three-match suspension at the start of the 2015-16 season.
Van Gaal was left frustrated by the Belgian midfielder's actions just 18 minutes after coming on as a substitute, and warned Fellaini that he risks dropping down the pecking order at United next season as a result.
"I do think Fellaini doesn't want to do that," said Van Gaal. "Because for him, it is unbelievably stupid because next season he starts in the tribune [the stand], and also in preparation, you start then more or less as a substitute."
McShane also took a blow to the head, and there was a delay to proceedings in the match that saw Hull relegated from the Premier League with Newcastle staying up by beating West Ham.
"It is not so good for him personally but I don't know if it is a red card," continued Van Gaal. "I cannot see that off the bench but when I see it takes seven minutes, I believe that the player was able to stand up, it shall be a worse tackle -- I don't know."
Van Gaal, who joined United straight after leading Netherlands to third place in the 2014 World Cup, said he was relieved to be finally able to take a break.
"I am happy now that the holidays are starting for me," he said, before saying he had already spoken to his players about their futures next season.
"I have talked with every player I think I have to talk to," he added. "The transfer period is a process, I have said that also in all my press conferences.
"I know which players have to go and which players have to come, but you never know if they come or if they go, because it is dependent on a lot of aspects."