​Sunderland boss Simon Grayson has challenged wantaway defender Lamine Kone to perform well if he wants to secure a transfer back to the top flight.

Kone has been the subject of intense transfer speculation over the last few weeks, linking him to a number of Premier League sides. Speculation around the player has been generated by his quality performances last season, despite being in the side that finished bottom of the league.

Bury v Sunderland - Carabao Cup First Round

With the giant 26-year-old playing well in Sunderland's opening games, Grayson has discussed the possibility of Kone's departure as well as a number of his other first team players, including Didier N'Dong.

Speaking before Sunderland's clash with Sheffield Wednesday on Wednesday, Grayson said: "While people are still here, if they’re thinking about options to leave, play well and make that happen.

"Kone? I think he’s up for the fight. By the sounds of it and the way he has played, he has looked very comfortable and shown his true quality. That’s the same of Didier and all the rest of the lads as well. Ultimately it’s about what they’re doing while they’re contracted for us.

"While the window is still open every club will be vulnerable to deals but also looking to do deals. We’re in the process of talking to clubs and that will be the case right up to the last minute. Martin Bain (MD) is dealing with the off the field stuff, and I’m concentrating on the games.

"I’ve got plans of x,y and z being here or not being here. You have to be one step ahead and aware of any eventuality. If we don’t lose any players, I’ll be more than happy, but you have to have plans in place in case something happens. While the window is still open, every club is vulnerable to players leaving."

It is thought that top flight sides West Ham United and Southampton are currently targeting a move for the Ivorian defender in an attempt to bolster their own back-lines.