Nicolas Anelka is upset that Chelsea want to sell him.
The Telegraph says Anelka had been expected to stay with Chelsea until his contract ends next June.
But he will be allowed to depart because Villas-Boas needs to create room in his squad, suggesting he might try to recruit more players than just a new central defender, expected to be Bolton Wanderers' Gary Cahill.
Chelsea are also determined to reduce the average age of their squad.
With Anelka's contract expiring soon, he is vulnerable, although the striker is thought to be dismayed at Chelsea's desire to move him on now.