Manchester United have sold striker Giuseppe Rossi to Spanish side Villarreal for a reported £6.7m fee.
Rossi spent time on loan at Newcastle and Parma last season
The 20-year-old American-born Italian signed a six-year deal on Wednesday.
United boss Sir Alex Ferguson said he tried to persuade Rossi to stay, promising the striker he would be given opportunities at Old Trafford.
But he added: "He wanted to have a go at first-team football. We've got a clause in his contract where he could come back to us at some point."
United signed Rossi as a 16-year-old from Parma and the Italian club were keen to secure his services once again after the striker helped them stay in Serie A with nine goals in 19 matches during a loan spell there last season.
They reportedly tabled a £5.4m bid for the Italy Under-21 international, but failed to clinch a deal.
United boss Sir Alex Ferguson often spoke highly of Rossi, who scored 13 times in 19 starts for the reserve team in his first season at Old Trafford.
He signed a new contract until 2010 last summer, with Ferguson hailing him as "the future of the club".
He went to Newcastle last season in a bid to play regular Premier League football but failed to win a regular place in the first team.
His loan spell in Parma was, by contrast, a huge success and Villarreal's offer was apparently too good for United to turn down.
Villarreal were looking for a new striker after allowing Diego Forlan, another ex-United player, to join Atletico Madrid for £14m.