Carlisle have disciplined six members of the first-team squad after reports of players having been out until 04:00 GMT less than two days before a game.
The players were seen out in the city in the early hours of Saturday and Keith Curle's side went on to lose 3-0 at home to York City the following day.
Manager Curle said a "maximum fine" had been imposed, along with the removal of "certain professional privileges".
The League Two club has declined to identify the six players punished.
They have also not confirmed whether or not they were drinking alcohol on the evening concerned, which followed a 1-0 win over Morecambe.
However, managing director John Nixon said in a statement on the club website: "If individuals felt it right and proper to offer an apology to the supporters publically, we would encourage them to do so at the earliest opportunity."
Former England defender Curle, who was appointed Carlisle boss in September, had promised a dressing room investigation into the allegations.
The 51-year-old said: "It was important for us to talk to the squad as a collective and to find out exactly what happened before we decided on our course of action.
"I appreciate that our supporters, who put a lot of time and effort into backing this club, have wanted to see a response as quickly as possible following on from the disappointment of the home game on Sunday and the release of this news on Tuesday morning.
"I can assure you that we share their concerns with what happened and we do not deem such actions as tolerable at this football club."
He added: "We need to make it clear that the club, the staff and, more importantly, the fans expect a certain level of professionalism from the players who represent them.
"I am sure this is a situation we will not face again."
Carlisle are 21st in League Two, just two points above the relegation zone, and are in action again on Saturday at Newport County.