Lazzari made his professional debut in the Lega Pro for SPAL on 31 August 2014 in a game against Pontedera. Flying under the radar for quite some time, since arriving in the Serie A for the 2017–18 season – following the club’s double promotion from the Serie C (2015–16) and Serie B (2016–17) – he has established himself as a main component in the Emilia-Romagna side’s success.