Sunderland's Jermain Defoe. Photo: Lee Smith/Reuters

Sunderland manager David Moyes has revealed Jermain Defoe has a clause in his contract which means the England striker can leave for free following the Premier League club's relegation.

Defoe could play his final home game for Sunderland against Swansea on Saturday following Moyes' admission that the former Tottenham star is able to walk away from the Stadium of Light at the end of the season.

With the Black Cats preparing for life back in the Championship next season, Moyes could have to do without Defoe, who has been one of the few bright spots in a miserable season on Wearside.

The 34-year-old's 15 goals gave Sunderland a brief glimmer of hope that they could have avoided relegation and Moyes admitted he was shocked to learn the club agreed to the clause when they handed Defoe a contract extension in June last year.

"We hope Jermain stays. Everybody at the club wants him to stay, all the supporters want him to stay, but it has to be Jermain's decision what he does," Moyes said on Friday.

"Yes, there's a clause in the contract, which is hard to take, I think. I would hope that in my time, if I had been the manager, I wouldn't have allowed a clause like that to be in there.

"But it is, and obviously we have to honour the contract."