It is also understood that Duff’s advisors are keeping a close watch on Manchester United’s pursuit of Ronaldinho because, given the choice, he would almost certainly choose to join the Barclaycard Premiership champions.

Souness told the Lancashire Evening Telegraph: “I can understand why he wants to talk to Chelsea but that doesn’t mean to say he’ll be signing for them.

“If he does end up going there then the money we’ll receive is a hell of a lot, not just in today’s market but the market of two years ago. It’s a phenomenal amount of cash.

“But we would be losing a top player. Left-sided players are very hard to come by and that’s why a man who could go out and bid for anyone in the world has gone for Damien, because the people who are advising him know that players in his position are very difficult to find.”

Souness and Blackburn are in Washington DC for a pre-season tour.

Duff came within minutes of flying out with the squad – he had even checked his bags in and gone through security on Wednesday before a call came through to stay in England.