David Moyes has accused midfielder Jeremain Lens of being "disgracefully disrespectful" to Sunderland after apparently claiming he might get the move he wants if they are relegated.
The 29-year-old Dutchman is currently on loan at Turkish club Fenerbahce under former Black Cats Boss Dick Advocaat, the man who brought him to the Stadium of Light in an £8million switch from Dynamo Kiev in July 2015, and earning rave reviews for his performances.
Advocaat is keen to strike a permanent deal for Lens and Sunderland are prepared to offload the player, who failed to make a lasting impact during his 13 months on Wearside, although no agreement is yet in place.
The former PSV Eindhoven man was widely quoted in the Turkish media this week suggesting that Sunderland's relegation from the Premier League might ease his passage, and that drew a furious response from Moyes.
He said: "It's disgracefully disrespectful to the club which holds his registration. You would hate to think that anybody who was connected to a club had said that."
Lens is perhaps the least of Moyes' worries at the moment as he attempts to keep hold of the players he does want after confirming that Sunderland, who entertain Stoke in the Premier League on Saturday, have rejected a bid understood to be in the region of £7million from Crystal Palace for full-back Patrick van Aanholt.
The manager revealed that Palace's move, which came barely a week after West Ham attempted to prise star striker Jermain Defoe from his grasp, was the latest in a series from potential suitors and was rebuffed unequivocally.
He said: "It's a permanent 'no' because we want to keep him. We have had bids for other players, so somewhere along the line, maybe we'll decide there'll be a bid we do take, but at the moment, I want to keep our best players, I want to try to add to the squad if I can.
"Ultimately there's always a price for somebody, but my plan is not to sell any players."
Sunderland's parlous financial position, as outlined by chief executive Martin Bain last month, means there will be very limited investment this month, and the need for prudence has been underlined by figures from UEFA which show the club recorded the 11th biggest net debt in Europe during the 2015 financial year.
Only Manchester United and QPR in England owed more than the 208million Euros - around £181.4million - for which Sunderland were in the red, a figure which equated to one-and-a-half times the revenue they collected during the same period.
Moyes said: "I wasn't aware how poor Sunderland's financial position was, but I think what the club has done is they have made it clear about the transfers and the money, that it had to be cut back, and that's what Martin explained.
"I don't think it really has a great effect on me, except that I can't go out and spend an awful lot of cash. But the bigger thing is you don't want a club that has got that much debt because it means it's going to make it very difficult."