Early career When offered a spot on the youth team of Parma, Rossi (then 12) and his father moved to Italy until
Manchester United bought his contract when he was 17. His first-team debut came on 20 November 2004, at home to
Crystal Palace in the fifth round of the
League Cup, as an 84th-minute substitute for
David Bellion. For his Premier League debut on 15 October 2005, he came on in the 78th minute for
Ruud van Nistelrooy and nine minutes later scored the last goal in a 3–1 win over
Sunderland at the
Stadium of Light. On 18 January 2006, in an
FA Cup third-round replay, he started and scored twice as United beat non-league
Burton Albion 5–0. Although Rossi did not play in the
League Cup final against
Wigan Athletic,
Nemanja Vidić (who made a seven-minute cameo at the end of the game) gave Rossi his medal in recognition of Rossi's contribution to the team's success in the earlier rounds. At the start of the
2006–07 season, Rossi moved to
Newcastle United on loan until 1 January 2007, where he was expected to gain some first team experience. He made his home debut on 24 September 2006. Rossi scored his only Newcastle goal in his first start on 25 October 2006, against
Portsmouth in a League Cup third round tie at
St James' Park. For the second half of the season, he was again loaned out, this time to his former club Parma, scoring nine goals in 19 league appearances.
Villarreal On 31 July 2007, Manchester United confirmed that Rossi had been sold to Spanish club
Villarreal for an undisclosed fee, reportedly around
£6.6 million (
€10 million). He scored his first goal for Villarreal on his debut against
Valencia on 26 August 2007. In his second season with Villarreal, Rossi had scored 12 goals in 30 league appearances, along with three goals in eight
Champions League appearances. In January 2011, he signed a contract extension with Villarreal until 2016. The
2010–11 season proved to be his breakthrough season, as he scored 32 goals in 56 appearances in all competitions, helping the club to a fourth-place finish in La Liga, scoring 18 goals, which qualified them for the
2011–12 UEFA Champions League, also helping Villarreal to the semi-finals of the
2010–11 UEFA Europa League that season, scoring 11 goals, and the quarter-finals of the
Copa del Rey. An anterior cruciate ligament injury on Rossi's right knee that he picked up in the 3–0 loss against Real Madrid on 26 October 2011 caused Rossi to be out for six months. Rossi re injured his anterior cruciate ligament of right knee in training on 13 April 2012, and was out for a further 10 months. At the end of his 6 year stay with Villarreal, he had scored 82 goals in 192 games in all competitions and became the club's all time top scorer. After 10 years of scoring his final goal for Villarreal in October 2011 in a match against
Real Zaragoza, his record was surpassed by
Gerard Moreno on 11 August 2021, after he scored a goal in the
2021 UEFA Super Cup match against
Chelsea.
Fiorentina On 4 January 2013,
Fiorentina came to an agreement with
Villarreal for the transfer of Rossi for a fee of approximately €11.8 million. On 7 January, Fiorentina held a press conference unveiling Rossi, where it was revealed the player had signed a four-year contract containing a €35 million release clause. On 21 May, the final day of the
2012–13 Serie A season, Rossi made his debut for Fiorentina as a substitute in a 5–1 win over
Pescara. On 26 August, Rossi scored his first goal in 23 months in Fiorentina's opening match of the
2013–14 Serie A season – a 2–1 defeat of
Catania. On 20 October, Rossi inspired Fiorentina to a 4–2 come from behind win over rivals
Juventus, netting a 14-minute hat-trick that condemned Juve to their first defeat in Florence for 15 years. On 5 January 2014, Rossi was substituted in Fiorentina's match against
Livorno as he suffered a second-degree sprain of his medial collateral ligament in his right knee. The blow was dealt by
Leandro Rinaudo, who tackled Rossi from behind in a manner so dirty that he drew international condemnation. Up to this point Rossi had been the leading goal scorer in
Serie A with 14 goals in 18 league appearances. Rossi returned from injury as a 69th-minute substitute in Fiorentina's 3–1
Coppa Italia final loss to
Napoli on 3 May. On 6 May, he scored on his Serie A comeback – a 4–3 defeat to
Sassuolo. On 14 August 2014, Rossi injured his medial meniscus of right knee in training. On 5 September 2014 Fiorentina confirmed Rossi would be out for 4–5 months. Rossi returned to the pitch on 30 August 2015, in a 3–1 away defeat to
Torino; later that week he also agreed with his club to take a salary cut. On 1 October, he scored his first goal since coming back from his injury in Fiorentina's 4–0 away victory over
Belenenses in the
Europa League.
Loan to Levante On 22 January 2016, Rossi returned to
La Liga by signing a loan deal until end of the season with
Levante, in order to gain playing time, and a place in the Italy national side at Euro 2016. He made his club debut on 31 January, scoring in a 3–1 away defeat to
Sevilla. On 13 March at the
Estadi Ciutat de València, he scored the only goal of a win over city rivals
Valencia CF, managed by his former United teammate
Gary Neville. On 8 May, he scored a late winner in a 2–1 home win over title contenders
Atlético Madrid, although the result was not sufficient to prevent the team from being relegated.
Loan to Celta Vigo in 2017 On 29 August 2016, Rossi signed a one-year contract with
Celta de Vigo, with an option for another year. He scored his first goal for the club on his debut, which came in a 1–1 away draw against
Standard Liège in Celta's opening group match of the
Europa League. He made his league debut with the club on 18 September, coming on as a substitute in a 0–0 away draw against
Osasuna. On 3 April 2017, Rossi scored a hat-trick in a 3–1 home win over
Las Palmas in La Liga; this was his first goal since he scored against
Espanyol on 25 September 2016, and his first hat-trick since 20 October 2013, when he scored three goals for Fiorentina in a 4–2 home win against Juventus. On 9 April 2017, Rossi suffered the fifth serious injury of his career when he ruptured the ACL in his left knee in a game against
SD Eibar, and was consequently ruled out of action for at least 6 months. Rossi became a free agent in July after Fiorentina allowed his contract to expire and he subsequently rejected an offer by Celta to remain with the Spanish side until January 2018.
Genoa On 4 December 2017, Rossi was signed by
Genoa on a free transfer. He made his debut for the club on 20 December, coming on as a second-half substitute in a 2–0 away defeat against Juventus in the round of 16 of the
Coppa Italia. He left Genoa at the end of the 2017–18 season. On 12 May 2018 Rossi failed a drug test following a Serie A match against
Benevento, testing positive for the banned substance
dorzolamide. Although the country's anti-doping prosecutor wanted Rossi to face a one-year ban for this offence, following a hearing with that took place on 1 October, Rossi was ultimately given a warning; afterward, Rossi's lawyer Sergio Puglisi claimed: "We don't understand how this substance ended up among Rossi's foods, there was no intentionality – the line of good faith and consistency prevailed." Rossi later
tweeted: "A nightmare of four months is over. I only want to think about football."
2018–19 free agency In January 2019, Rossi started training with his former club, Manchester United. In February of that year, Rossi was reported to have been invited to train with
MLS side
Los Angeles FC. On 14 October, his former club Villarreal announced that Rossi would start training with their first team. In an interview with Italian daily newspaper
Corriere della Sera in December 2019, he stated that he was "ready to help out any
Serie A team".
Real Salt Lake Following a trial with the
MLS club, Rossi was announced as a
Real Salt Lake player on 27 February 2020. He made his club debut on 29 February, coming on as a late second–half substitute in a 0–0 away draw against
Orlando City in the MLS. His contract option was declined by Salt Lake following their 2020 season.
SPAL On 19 November 2021, after a few weeks of training with the club squad, Rossi was formally announced as a new signing for Italian
Serie B club
SPAL, on a deal until the end of the season. On 17 February 2023, after being without a club for half a year, Rossi returned to SPAL on a deal until the end of the season. He retired at the end of the 2022–23 season on 22 July 2023. ==International career==