Manchester United fear David de Gea will leave in the summer as they look to Serie A for goalkeeper replacements

Inter’s Samir Handanovic is currently the leading candidate to replace the Spaniard with Milan’s highly-rated 18-year-old Gianluigi Donnarumma also an option

David de Gea looks increasingly likely to leave Manchester United this summer (Getty)

Manchester United have started investigating alternative goalkeeping options like Internazionale’s Samir Handanovic and Milan’s Gianluigi Donnarumma, amid growing worries that David de Gea could leave for Real Madrid in the summer.

The Spanish club have made a new number-one one of their top priorities for the next transfer window, and have resurrected their long-standing interest in De Gea, but are also looking into signing Thibaut Courtois from Chelsea.

The Belgian has been considered the slightly more likely option, but those close to him say he is still “undecided” on his future, and the London club are also bracing themselves for a summer of tough negotiations with the Bernabeu given the simultaneous interest in Eden Hazard.

De Gea’s situation is different, given that it is known he and girlfriend Edurne Garcia have long wanted to return to his home city, with United having sanctioned a sale in 2015 only for it to infamously fall down due to administrative issues at the last minute.

The 26-year-old subsequently signed a new contract, but the belief has always been he would eventually go to Real Madrid, and there are growing concerns among the United hierarchy and the playing squad that could finally be the case this summer.

As such, United have started to look at potential replacements, with Inter’s Handanovic currently the leading candidate. The 32-year-old Slovenian has attracted similar Premier League interest from Liverpool and Manchester City, but not to the extent of United. Milan’s highly-rated 18-year-old Donnarumma is also an option and represented by Mino Raiola, who is similarly agent to Paul Pogba and Zlatan Ibrahimovic.

United midfielder Ander Herrera cast further doubt on De Gea’s Old Trafford future last week, when asked the situation while on international duty with Spain.

De Gea's future at Old Trafford looks uncertain at best (Getty Images)

“It’s difficult for him [De Gea] to one day be at one place, and then to be at another the next,” Herrera said.

“He learned a lot from this. It has made him more mature. I want him to be the one defending Manchester United’s goal.

“Hopefully it will be like that, but anything can happen in football.”