The 20 year old has joined the La Liga outfit in an estimated £6million deal after deciding he wanted more first-team opportunities than he was likely to get at Old Trafford this season.

"We have put a clause in the contract, so maybe he will come back to us at some stage," the Scot told MUTV.

"We wish Giuseppe well and we know he will do well at Villarreal.

"It was a difficult decision to let him leave. I had several meetings with him to try and convince him that he would get plenty of football with us this season and all he needed was a bit of patience.

"But, having been on loan last season, he wanted first-team football all the time."