Rome - Italy prop Martin Castrogiovanni could be out of the rest of the Six Nations after cracking a rib during Saturday's 19-15 defeat to England at the Stadio Olimpico here.
Following tests with Italy's medical department the Leicester Tigers tight-head is expected to be out for between 30-40 days.
That means he faces a race against time to be fit for either of Italy's final two tournament matches away to Wales on March 10 or at home to Scotland a week later.
Castrogiovanni was forced off during the first half after a relatively innocuous looking clash when carrying the ball.
As well as the Italian Rugby Federation announcing a sell-out crowd before Saturday's match at the 72 000-capacity Stadio Olimpico - although on game day there were visibly some empty seats - Italian TV also claimed record viewing figures for the game.
Sky Sport, which broadcast the game live, said they received an average of 290 420 viewers, a 30 percent increase on their previous record figures during last season's Six Nations for the historic home victory against France.