Celtic will have to move swiftly if they want to secure the services of Real Sociedad full-back Xabi Castillo.
The defender’s contract with the Spanish club expires at the end of the month and while a move to another club in his homeland would cost around £2million, the Parkhead club could land him for a bargain basement fee of just £100,000.
Castillo has confirmed several clubs in England, Italy and Greece want him, but is looking for Celtic to confirm their interest by making a ‘proposal’ to his current club.
Xabi said in The News of the World: "I have interest from Italy, England and Greece, but what I want is a proposal from Celtic."
However his agent, Joaquin Barcena, warned the Glasgow giants they will have to act quickly as Marseille have entered the ring by declaring their interest.
"Xabi has instructed me to find a club with a 'British' accent and already stated Celtic would be perfect,” Barcena said. “Others have enquired about him, though, so nothing is certain yet.
“Hopefully, we can come to an agreement soon."