The 20-year-old, who scored one of Italy’s tries in Dublin, came off minutes from the end in tears.
The detached bicep injury is expected to keep him sidelined for at least four months.
Azzurri coach Kieran Crowley has had to postpone the announcement of his World Cup squad from this Thursday until August 22 due to a series of injury worries.
The World Cup kicks off next month on September 8 in France, and will conclude with the final on October 28.
The federation said on Monday that prop Marco Riccioni, who came off after 10 minutes in Dublin, suffered a knee injury and scrum-half Stephen Varney, who was replaced at half-time, hurt his shoulder.
It said the situations of both players would be re-assessed in the coming days.
The team have come away from both recent warm-up matches against Scotland and Ireland with losses, and now face Romania and Japan in their final preparation matches before the World Cup.
Italy’s opening match is against Namibia on September 9 in Saint-Étienne.
They face a massive challenge to finish in the top two of Pool A to qualify for the quarter-finals for the first time as hosts France and the legendary New Zealand All Blacks are in the same group, along with Namibia and Uruguay.
ANSA
