Tottenham Hotspur non-executive director Sir Keith Mills has told the Evening Standard it is "very difficult" to ensure an unsettled player remains at the club, amid speculation over Gareth Bale's future.
Bale has been strongly linked with a move to Real Madrid this summer, although Spurs are reluctant to sell the Wales international despite a reported €100 million bid being offered by the Liga club.
The forward signed a four-year contract at White Hart Lane in 2012 but Mills accepts the club are almost powerless to retain his services.
"We very much want Bale to stay," Mills told the Evening Standard. "If a player is desperate to leave, it's very difficult to force him to stay.
"We've seen it in other clubs. Even if he has a contract, you can't force somebody to play for you.
"This summer, we are investing in a great squad and we hope that provides us with Champions League football next year and we start to win trophies, FA Cups. That's what Tottenham need. We have made some good acquisitions."
Spurs boss Andre Villas-Boas has already signed Paulinho and Roberto Soldado, and Mills has said further additions are in the offing.
"There are others in the pipeline," he added. "Strikers are very high on AVB's list of priorities and Daniel Levy is trying hard to make sure we have strength up front. It's a really exciting time to be at the club."