Manchester United boss Jose Mourinho is extremely concerned he could lose goalkeeper David de Gea to Juventus on a free transfer when his contract expires.
The 27-year-old has a deal in place at Old Trafford until next summer, although United do have an option to extend it by a further year if they choose to.
De Gea, a long-term target for Spanish giants Real Madrid, had been expected to sign a new contract at United after Thibaut Courtois left Chelsea for the Bernabeu earlier this summer.
According to The Times, the Serie A champions are hopeful of recruiting a goalkeeper to match the calibre of club icon Gianluigi Buffon, who left Turin after 17 years this summer.
With no discussions on a new deal taking place so far, De Gea knows that Juve are in pole position to get his signature and wants a move away, it has been claimed.
The Italians are hoping to pick the bones of United once again after they took Paul Pogba from Old Trafford in 2012, only to sell him back for £100 million five years later.
Andrea Pirlo, Dani Alves, Sami Khedira, Kingsley Coman, Emre Can and Fernando Llorente have all joined the club on free transfers in recent years.
A Manchester United source told The Times: "De Gea played against his future club on Tuesday. Juve are an expert in intelligent deals. If United don't sell him in the summer, Juventus will wait until the end of his contract."
United paid a previous British record fee for a goalkeeper of £18.9m when they signed De Gea from Atletico Madrid in 2011.
He played against his potential future employees on Tuesday night as United were beaten 1-0 by Massimiliano Allegri's side in the Champions League thanks to Paulo Dybala's 17th-minute winner.