Sunderland have confirmed they are in talks with several parties over the possible sale of the club.Black Cats owner Ellis Short has made no secret of his desire to sell his 100 per cent stake and it has been reported he was in advanced talks with a mystery German consortium.But the north-east club have revealed if the sale is not completed within a "defined time frame", Short will pull out of negotiations and press on with plans for next season.The Sky Bet Championship club said their search for a new manager following the resignation of David Moyes last month had been affected by the uncertainty over its ownership.Derek McInnes has turned down the chance to replace Moyes after talks with the Black Cats and announced his decision to remain at Aberdeen on Thursday."Since the end of the season, our focus has been to appoint a new manager," Sunderland said in a statement on their official website."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."The recruitment process, whilst still very much active, cannot therefore be concluded imminently."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 AFC are at the heart of any decision regarding its future."We are of course acutely aware of the need to act swiftly to appoint a manager and, to ensure that this is the case, have placed a time limit on discussions regarding a potential sale."If discussions are not concluded within our defined time frame, we will terminate the process and move swiftly and positively forward with plans for the new season."Detailed pre-season preparations are already in place and our aim is to do everything we can to ensure Sunderland's return to the top flight."Consortiums from China and the Middle East have previously shown interest in taking over the club, but failed to make formal offers. Irish-American businessman Short is understood to have invested more than Â£200million into Sunderland since taking a controlling interest in 2008. Preston boss Simon Grayson and former striker Kevin Phillips remain in the frame to succeed Moyes.