Hull boss Steve Bruce has demanded an apology from out-of-favour defender Paul McShane.
The Republic of Ireland international, who is a fans' favourite and the club's longest serving player, has featured just six times this season and has not been seen since the Burnley defeat on November 8.
Since then relations appear to have deteriorated significantly, with the 28-year-old sent to train with the development squad.
He has also taken to retweeting fan comments about his continued exile, an act which has not gone down well with his manager.
And while Bruce would not elaborate on the precise reasons for the current stand-off he was clear that there was only one way to resolve it.
"I heard all this nonsense about what's on Twitter and the rest of it but it's quite straightforward: Paul knows exactly why he's training with the Under-21 squad at the moment," said Bruce.
"He's been quite quick to reveal that he is in there and I hope he comes out and tells the reason why.
"If he apologises to myself and to the squad then he will come back into the fold. It's entirely up to Paul."
Unless McShane works quickly he can expect to miss out once more against former club Sunderland on Boxing Day.
With loanee Hatem Ben Arfa also having played his last game for an unimpressed Bruce, Tom Huddlestone and Jake Livermore both suspended and Michael Dawson, Mohamed Diame and Robert Snodgrass all injured, there is as much first-team talent unavailable as fit and ready for action.
Bruce is eager for captain Curtis Davies to pull through after suffering a calf injury against Swansea last weekend.
"We don't know about Curtis, we'll have to see how he is, but he is extremely sore," he added.
To combat the team's personnel troubles, Bruce has recalled Tom Ince and Maynor Figueroa from their respective loan spells at Cardiff and Wigan.
Neither player were knocking down the door before being sent away earlier this season, but may well find themselves involved in the busy festive period.
"Ince and Figueroa have trained with us for the first time on Tuesday," said Bruce.
"We needed them to get games. They've had a few but not as many as I'd like, and, with the injuries and suspensions, we welcome them back."