Peterborough boss Darren Ferguson says it will be "difficult" for Christy Pym to get back into his plans as the goalkeeper "overstepped the mark" after their defeat at Reading on Tuesday.
Pym was left out of the squad for their 3-0 win over Birmingham on Saturday as David Cornell made his Posh league bow.
Former Exeter keeper Pym, 26, has made 94 appearances since joining in 2019.
"In a dressing room after a game I like to keep it there, but I knew the question would come," Ferguson said.
He told BBC Radio Cambridgeshire: "I've made a decision that it's going to be difficult for that boy to get back.
"He overstepped the mark on Tuesday night. He apologised for it but I've got to have discipline - there's going to be criticism and you've got to take it like a man."
Ferguson said it was "too early" to judge whether Pym will play for the club again, adding that he has "made a decision" and will "stick by it".
"There's certain things as a manager you have to do and there's certain things you can abide by, but that wasn't one of those," he added.