Chelsea could face a transfer ban after manager Jose Mourinho admitted to making a personal approach to Real Madrid midfielder Luka Modric, seemingly without the cub's permission.

Mourinho has admitted to a Croatian newspaper that he attempted to convince Modric to move to Stamford Bridge this summer during a private phone call, but was turned down by the former Tottenham Hotspur midfielder.

The admission could force Real into submitting a complaint to Fifa regarding the approach which if followed up would see Chelsea facing a lengthy transfer ban.

The Blues were banned in 2010 from making transfers for two windows after being found to have induced Gael Kakuta to joining them from Lens, however the Court of Arbitration for Sport overturned the punishment.

But Chelsea now face action after Mourinho's public admission that he contacted Modric regarding a move back to the Premier League.

"I called Modric only privately but he doesn't want [to join] Chelsea," Mourinho told Croatian newspaper Sportske Novosti

"You know I really appreciate Luka Modric and his qualities. But he stays in Real Madrid."

Modric's role in the Real team is clouded with uncertainty after the club clinched the signing of James Rodriguez from Monaco, with Carlo Ancelotti facing a selection dilemma ahead of the new season.

Chelsea have already made four signings this summer in the form of Cesc Fabregas, Diego Costa, Filipe Luis and Didier Drogba and Mourinho said earlier this month that the club's activity in the widow is over.

During Modric's days with Tottenham, the La Liga and Champions League winner was constantly the subject of interest from Chelsea but were constantly denied securing a deal by chairman Daniel Levy.

The Spurs chief eventually allowed Modric to leave White Hart Lane in the summer of 2012 but it seems as though Chelsea's interest has not relented.