The 26-year-old Wales international, currently on loan with Leeds from Sunderland, has been kept on by Kevin Blackwell, but not without a reprimand.
It is most likely Oster has been fined the maximum two weeks' wages, with Blackwell saying: "We sat down and talked to John and found out the facts. We told him that at Leeds United we cannot accept what he did. We have been down that road before as a club and we didn't want to go down it again.
"The police threw it out, so there's nothing pending. It was just a question of us having a chat with him and reminding him of his responsibilities.
"He has been dealt with and punished by the club and that's it. End of story."