Italy's hopes of reaching the Rugby World Cup quarter-finals for the first time suffered a significant blow on Tuesday as highly-rated back Tommaso Menoncello was ruled out due to a serious left arm injury.

The dashing 12-times capped centre/wing underwent scans on Monday on the injury he suffered in Saturday's 33-17 Test defeat at the hands of Ireland, leaving the pitch in tears.

The Treviso star is to undergo an operation on Thursday but the Italian Rugby Federation told AFP he "would not be able to play at the World Cup."

The tournament begins on September 8 with Italy beginning their campaign a day later against Namibia in Saint-Etienne.

Menoncello's absence makes what was already a big ask for the Azzurri, although, much improved under coach Kieran Crowley, to progress to the knockout stages for the first time. 

They may have to be satisfied with likely wins over Namibia and Uuruguay as their other two Pool A opponents are hosts France and three-time champions New Zealand.

Crowley had to delay his unveiling of the squad by 10 days -- it will be on August 22 -- due to a series of injuries in the Irish match.

Saracens prop Marco Riccioni was substituted after just 10 minutes having taken a knock to the knee and Gloucester scrum-half Stephen Varney went off after half-time with a left shoulder problem. 

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