Keane has been one of the Premier League’s standout defenders this term

Michael Keane is set to become José Mourinho’s first summer signing as Manchester United edged closer to recapturing their former centre back from Burnley.

United and Burnley are said by sources to be “very close” to agreeing a deal of about £25 million for the 24-year-old, beating Everton in the race to sign the defender.

Keane, far left, began his career at United before leaving in 2015 JOHN PETERS/GETTY IMAGES

Keane’s signing would put the future of Chris Smalling in doubt, particularly if United reignite their interest in Victor Lindelof, the Benfica centre back.

Despite Smalling’s assertion that he has a “very good relationship” with Mourinho, it is understood that the United manager has been unhappy with some of the defender’s performances and commitment since he replaced Louis van Gaal last summer.

Smalling has started only 12 Premier League games