Manchester United chiefs are reportedly unhappy about failing to put a sell-on clause in Michael Keane's contract when he signed for Burnley.

The 23-year-old has impressed at Turf Moor since making the permanent switch from Old Trafford in January 2015, leading to talk of a potential £25m move to Chelsea in the New Year.

According to The Sun, United will not receive any cash if the Englishman - who they sold for just £2.5m after he failed to make the breakthrough at Old Trafford - does indeed join another club in the coming months.

An insider is quoted by the newspaper as saying: "The club are kicking themselves over it and some people are now keeping their heads down. There is a fear they could be hearing 'we told you so' in the near future. He has always been highly-rated by United's reserve coaches."

Keane was called up to the senior England squad for the first time earlier this week after fellow defender Glen Johnson was forced to withdraw through injury.