Giuseppe Rossi will miss Euro 2012 and face a further six months on the sidelines after tearing his Anterior Cruciate Ligament (ACL) in training on Friday.
Rossi, 25, was only just easing his way back into training after a similar injury suffered in October and now sees his European Championship dream shattered.
The former-Manchester United youngster was expected to be an important player for Cesare Prandelli's side this summer, but will now undergo surgery on his knee once more.
The American-born star will also miss the start of next season for Villarreal, a huge blow for a side already feeling the absence of their star striker.
Since his arrival from Old Trafford in 2007, Rossi has notched 82 goals for the 'Yellow Submarine' who have found themselves scrapping relegation in his absence.
Rossi has made 27 appearances for Italy, scoring six times for the national side.