 Protti started his career with his hometown club Rimini in 1983; although he played for several Italian club sides throughout his career, including Lazio and Napoli, he is mostly remembered for his time with Livorno, where he established himself as a legendary figure in the club's history during his second spell with the side, and eventually remained with the team until his retirement.Along with Dario Hübner, Protti is the only player to have won the top scoring titles in Serie A, Serie B, and Serie C1; he is also the only Serie A top-scorer to have suffered relegation with his club (Bari, at the time).Protti spent the majority of his early career playing for teams in lower divisions; he made his career debut in Serie C1 at the age of 16, with his home-town club Rimini, on 27 May 1984.