Sir Alex Ferguson has revealed Manchester United have first refusal on Giuseppe Rossi should Villarreal want to sell the Italian Under-21 international.
Rossi 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.
Ferguson did his best to persuade the 20-year-old to stay with United but after scoring nine goals in 17 games to effectively keep Parma in Serie A last term, Rossi was anxious not to find himself back in the Red Devils reserves.
So, in accepting Rossi's wishes, Ferguson instead ensured he would be able to buy the New Jersey-born striker back should the need arise.
'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.'
Rossi has signed a six-year contract with Villarreal, where he is effectively replacing another United old-boy, Diego Forlan.
Ferguson will now hope to tie up the transfer of Carlos Tevez reasonably quickly as, with Alan Smith seemingly certain to leave before the August 31 deadline and both Ole Gunnar Solskjaer and Louis Saha on the injured list, he is likely to have only one recognised out-and-out striker, Wayne Rooney, in his squad for Sunday's Community Shield showdown with Chelsea at Wembley.