Sunderland are exploring the possibility of suing former Watford loanee Didider Ndong.

The 24-year-old midfielder failed to make an appearance for the Hornets after arriving on loan at Vicarage Road in January and has been AWOL since returning to Sunderland in the summer.

Both he and teammate Papy Djilobodji, who was given permission to miss pre-season training but only returned to the club last week, could now be sued by the Black Cats for breach of contract.

The League One club believe Ndong is attempting to drive down his value so severely that they are forced to terminate his contract.

Speaking to Talksport, Sunderland chairman, Stewart Donald, outlined the Wearside outfit’s stance.

“I’m certain we are allowed to fine them,” he said. “But the question is whether they’ve done enough in breach of contract [for us] to terminate their contracts and pursue them for wilfully devaluing themselves.

“Didier Ndong has shown no interest in returning to the club whatsoever. We don’t even know where he is.

“They can’t move now and we don’t think they’ve behaved well enough for us to say, ‘All right we’ll pay you’ never mind play them, because neither of them are in condition to play.”