In 2012, Rizzo was selected by Italy's head coach Jacques Brunel to play in his first Six Nations. On 23 June 2014, Rizzo along with teammate Leonardo Ghiraldini made his move to join Leicester Tigers in the English Aviva Premiership from the 2014–15 season. In the same year, after playing in the 2015 Rugby World Cup in England, Rizzo tore his anterior cruciate ligament, in the same knee where he suffered another bad injury in 2002, missing the rest of the season. He spent the early part of the 2017–18 season for Edinburgh Rugby of the Pro14 on a short term emergency loan. He returned to Leicester in December and was immediately named in the club's Champions' Cup squad. On 30 May 2018, Rizzo returned to Petrarca on a two years deal where he ended his career.