There was a season (10/11) when he was at Villarreal where he was basically the best player in the league alongside Messi and Ronaldo, with 32 goals + 11 assists in 52 games.

Then he gets a series of brutal knee ligament injuries, only playing 15 matches over the next 2 seasons, failing to score.

In January 2013, Rossi moves to Fiorentina, and in June 2013, Barcelona sign Neymar.

Then in the 13/14 season, Rossi made a return to form at Fiorentina, scoring the above hattrick, and scoring 14 in 18 league matches before injuring his knee ligaments again in January.

If not for those injuries I’m sure he would have excelled at Barca.