The 30-year-old has been linked with a host of clubs over the summer and although the Hammers have yet to receive an offer, the boss believes that one may arrive soon.
"At the end of the day, Scott's position is delicate because at any one time, someone will hit the numbers that we would value him at,” he told The Sun.
"If that's the case and it's the Premier League - a place where he wants to be - he will be gone. It would be wrong of me to plan with Scott."
West Ham begin their Championship campaign on Sunday, when they host Cardiff City at Upton Park.