Six Nations - Italy lose 'tired' Canavosio
Fabio Semenzato, brought into the squad this week after usual number nine Edoardo Gori injured a shoulder in last weekend's opening defeat by Ireland, will now make his debut at Twickenham.
"Before training at Twickenham this afternoon, Pablo, with a great sense of responsibility towards the team, informed us that he was still suffering from general fatigue and didn't feel up to being possibly used for 80 minutes," team manager Luigi Troiani said in a statement.
"The coaching staff have therefore decided to start Semenzato and use Canavosio if needed in the course of the match."
Canavosio, who has 33 caps but has consistently failed to fully convince coach Nick Mallett, replaced the injured Gori against Ireland.
Mallett jettisoned scrumhalf Tito Tebaldi during the November tests as he struggles to find the right formula to avoid embarrassment for the modest side ahead of September's World Cup.
The South African, uncertain to be offered another contract by Italy after the World Cup, has also constantly tinkered at flyhalf with Luciano Orquera due to make another comeback on Saturday.