Rossi played for SPAL in Serie B last season.
Having spent time in Manchester United's youth ranks as a teenager, Rossi made five Premier League appearances in the 2005/2006 season and scored one goal.
Rossi's career was hampered by injuries but he found some stability at Villarreal, where he scored 18 goals in 36 La Liga games in the 2010/2011 season.
A nomadic career saw him turn out also for Newcastle United, Parma, Fiorentina, Levante, Celta Vigo, Genoa and Real Salt Lake.
Rossi won 30 caps for the Italy national team and scored seven goals.
Rossi posted on Instagram: "Today I announce my retirement from the beautiful game. It’s been an unforgettable journey!
"From running around the backyard as a kid with a ball at my feet and having my father as a coach, to playing at the highest level of football possible, in the most beautiful stadiums football can offer and playing with/against the best players and clubs in the world….
"I’m eternally grateful to have been a part of this game. My dreams came true. My life is fulfilled.
"All I ever wanted was to be the best player I could be. I dedicated every ounce of me, shedded blood, sweat and tears for this game. I can leave the game peacefully, knowing I did all I can possibly do to achieve my goals.
"My journey is unique. A lot of ups but also some downs. Those down moments (mostly injuries) never defined me. My purpose was stronger than any obstacle that was in front of me.
"I never stopped dreaming when things I couldn’t control got in my way. I love the game so much that I could’ve never given up.
"That is why I’m writing this with a heavy heart but a big smile on face - I’m proud of what I accomplished!
"To my family…your sacrifices and endless support gave me the strength and courage to achieve things I thought were unreachable. Thank you.
"To my clubs…it was an honor being by your side and representing your shirt! I wore it proudly and gave it my all each and every game. Thank you for your trust in me.
"To my teammates…so many battles on the field together, so many amazing moments shared off the field. Thank you for being important figures during my career that challenged me to be the best player I could be.
"To the fans…the game wouldn’t be the beautiful game without you. You have all been by my side throughout my 19 year career. We shared some moments that will last a lifetime! Thank you.
"I will truly miss the game but I know it’s time. On to the next chapter..".
