New West Ham manager Avram Grant has indicated that Matthew Upson should leave the club if he is not fully committed.
The England defender has one year left on his contract at Upton Park, but is understood to be a £7million target of Sunderland.
West Ham narrowly avoided relegation from the Premier League last season and Upson is thought to be frustrated by the club's struggles.
But Grant, who has signed a four-year deal as successor to Gianfranco Zola, has previously said that he wants to keep the 31-year-old.
However, the former Chelsea and Portsmouth boss does not want players who are not 100 per cent dedicated, saying in the Daily Mirror: "We'll do everything to keep Upson, but West Ham fans deserve players who want to play for the club.
"I want players like that because I think we'll have a great future. It will be good for us and good for the players. Of course Matthew is one of them."