The young forward impressed at United and on loan spells with Newcastle and Parma - but in the summer of 2007 he was sold to Villarreal for £6.6 million.
A year later he was one of Europe’s most in form strikers, and a regular in the Italian national team.
In 2010-11 he was sensational, scoring 32 goals in 56 appearances, and for 2011-12 it appeared that the career of the then 23-year-old from Teaneck, New Jersey was going in one direction.
Then, it all went wrong.
On the 26th October 2011 Rossi tore his anterior cruciate ligament in a game against Real Madrid and he was out for six months, in April 2012 he did the same injury and his career looked in tatters.
But despite only playing a handful of games in the past 18 months he was still revered in Italy as one of their great attacking hopes - and Fiorentina remembered that.
They took a risk, and in January splashed out €10 million on the signature of the 27 caps Italian international - despite the fact he was still recovering from his serious injury.
And now he has completed his amazing turnaround - after receiving a recall for the Azzurri for their upcoming World Cup qualifiers.
Rossi has been in great form for Fiorentina this season, scoring six goals in eight games for La Viola.
And now he is set to play his first game for Italy since exactly two years ago, when he played in a European Championships qualifier against Serbia on October the 7th 2011.
For Rossi it is just reward for his long road to recovery, which has seen him face the very real prospect of never playing professional football again on more than one occasion.
Rossi was popular at United, and no fans will begrudge him his most recent call-up.
With things looking bright for the 26-year-old, he will now just hope to bag a goal in the game with Denmark on Friday - to truly announce to the world that Rossi is back!
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