The American forward is reportedly refusing to play for the Cottagers, and has been left out of the squad for their Premier League opener against Norwich City.
"Clint was not involved over the last four weeks so he is not going to be in the squad," confirmed manager Martin Jol. "He is not committed to the club. He wants to leave.
"I would like to keep him, but I think it's impossible. It's a sad and an almost embarrassing situation."