Man Utd keeping tabs on David de Gea's replacement?

Manchester United are reportedly keeping tabs on Porto goalkeeper Diogo Costa ahead of a possible transfer approach.

David de Gea has been an undisputed goalkeeper for the Red Devils over the past decade, but his future is now uncertain.

He has entered the final year of his £350,000-a-week deal, and the club are not keen on triggering the optional 12-month clause.

They seem willing to get him off their wage bill, and this could coincide with the purchase of a highly-rated goalkeeper.

Costa has recently become Portugal's number one with his strong displays, and the 23-year-old could be De Gea's replacement.

According to A Bola, the Red Devils were keeping tabs on his progress during Porto's 4-1 win over Braga in the Primeira Liga.

Aside from the shot-stopper, the club also had an eye on the talented centre-back David Carmo, who has been tipped for big things.

Carmo has been a mainstay in the Porto line-up this campaign. He has stayed injury free since his move from rivals Braga.