Sunderland hope to resolve the ongoing dispute with Papy Djilobodji by the middle of November.
In mid-September, Sunderland served the £8million defender notice his contract was to be terminated, a decision he appealed.
Donald has now revealed the case is due to go to court in mid-November unless a settlement can be reached beforehand.
“The legal teams are discussing with each other whether we can reach an amicable agreement between now and then but we’re pretty firm on our stance," revealed Donald.
"We feel we’ve been wronged and we don’t feel we were wrong to do what we’ve done. If he wins, then he comes back.
“I’m sure if he comes back he probably thinks in January he’ll be departing but we won’t be best pleased," he told BBC Radio Newcastle.
Sunderland retain Djilobodji's registration until the matter is resolved and there is almost zero chance of him ever playing for the club again.
He wouldn't be able to sign for a new club until January if he lost his case as he would have been made a free agent after the last window closed.
The club gave Djilobodji written permission not to return for pre-season training in July at the player's request, with the 29-year-old eager to find a new club. He was told, however, to stay fit in that time.
He didn't return to the Academy of Light until mid-September, well after the agreed date, and was put through a series of fitness tests as any player would returning for pre-season.
A Sunderland statement at the time said he 'comprehensively failed that test'.
Djilobodji and Didier Ndong - who has since left the club - were both AWOL throughout August.
On the ongoing Djilobodji case, Donald added: "I don’t think the footballing world has picked up how serious this is,.
"From our perspective we’re saying we terminated his contract because he has wantonly and knowingly disregarded his contract of employment and breached it on numerous occasions for numerous different things. He shouldn’t be allowed to do that. We’re saying on that basis we should terminate [his contract].
“If we’ve got that wrong, if the player wins the case and can come back what we’re actually saying is the contract’s not worth the paper it’s written on so what’s the point in paying [for example] £15m for a player that can actually decide he doesn’t want to train?”
Earlier in October Sunderland confirmed the departure of Ndong.
The Gabonese international was served notice under his contract in September after failing to report for pre-season training.
An amicable agreement was then reached whereby there is an agreement with the player for a payment by way of compensation upon his signing for a new club.