Born in Arcene, Bergamo, Vavassori started his playing career with Atalanta, where he made his Serie A debut in the 1971–72 season.
During his stay with the club he won several tournaments and trophies, including a Primavera national title and a Torneo di Viareggio in 1993.
[3] In 2004, Vavassori was appointed head coach of Serie B team Ternana, but resigned two weeks later, citing a falling-out with his players.
On 18 April 2007, Vavassori was appointed at the helm of Avellino, another Serie C1 club, to fill the position left vacant by the sacking of Giuseppe Galderisi.
[9] In May 2010, he was appointed at the helm of Verona to replace Gian Marco Remondina, who was sacked after he failed to guide his side to win direct promotion to Serie B following a shock 1–0 home loss to Portosummaga.