Liverpool striker Peter Crouch is ready to take advantage of the 'Webster law' and quit Anfield at the end of the season.
The Sunday Telegraph says Crouch is carefully considering exploiting the ruling, one of several options open to the England striker whose current deal expires at the end of next season.
Barnett said clubs had nothing to worry about if they behaved responsibly: "Certainly it will change the way things are conducted and we are probably heading for a period of shorter contracts. But I've never heard of a player volunteering to leave a club when he is happy and being well-paid."
Whether Crouch is happy is another matter, however; he played yesterday, but has started only six Premier League games this season.
Although the rule applies only to cross-border transfers, Graham Shear, one of the country's top sports lawyers, says this was an unviable restraint and "would certainly be challenged".