Sunderland confirmed on Friday that they are in talks with several groups over the potential sale of the Championship club.
Black Cats owner Ellis Short has been keen to sell up for some time and it was recently reported the American is in advanced talks with a German consortium.
But Sunderland have revealed if the sale is not completed within a "defined time frame", Short will pull out of negotiations because the club's search for a new manager had been affected by the uncertainty over its ownership.
Aberdeen boss Derek McInnes has turned down the chance to replace David Moyes, who quit following Sunderland's relegation from the Premier League last season.
"Since the end of the season, our focus has been to appoint a new manager," a Sunderland statement read.
"Recently, however, discussions have been entered into with parties who have expressed an interest in acquiring ownership of the club.
"With this backdrop, we have been unable to give the assurances any potential candidate would need regarding the plans a new owner could have for the manager's position.
"In talking to parties who have shown interest in acquiring the club, owner Ellis Short is determined to make sure that the best interests of Sunderland are at the heart of any decision regarding its future."