Italy have yet to reach the knockout stages of a Rugby World Cup and it will be a major surprise if they emerge as one of the two quarter-final qualifiers from a pool also featuring Ireland and France.

While most of the attention following their narrow 23-19 warm-up defeat by Wales in Cardiff last weekend centred on the World Cup-ending injuries suffered by Welsh backs Leigh Halfpenny and Rhys Webb, Italy also suffered a blow of their own.

Azzurri captain Sergio Parisse had to undergo surgery to drain a haematoma -- a swelling of clotted blood -- in a muscle in his left leg after suffering a knock in Cardiff.

The 31-year-old Argentine-born No 8 is a crucial figure for Italy.

Not only has he won 112 caps for the Azzurri but for much of that time Parisse has been Italy's star performer and the one player from the country who would figure in a composite World XV.

The Italian federation has said that Parisse was currently undergoing treatment with his Paris-based club Stade Francais and would not meet up with the Italy team in Rome on September 12, but instead link up "at a later date" in England.

"The goal is to optimise as much as possible the recovery process and to avoid any movements that are not strictly necessary," it said. "Further updates on the player's condition will be issued after the national team has gathered."

Italy suffered a further setback on Thursday when centre Luca Morisi was ruled out of the World Cup completely because of a torn ligament in his right knee suffered in the defeat by Wales.

That match also saw Gonzalo Garcia laid low with an ankle problem but he is expected to continue his rehabilitation with the rest of the squad.

It all adds to the stress of an Italy side coached by Frenchman Jacques Brunel ahead of their tournament opener against France at Twickenham on September 19.

Up front prop Martin Castrogiovanni remains one of the world's best-known scrummagers although, at 33, he is now entering the final phase of his Test career.

Italy have beaten both France and Ireland in the Six Nations, although both these successes came on home soil, while huge defeats -- they lost 48-7 to fellow strugglers Scotland last month -- remain an all too common feature of their Test record.

Typically, the defeat in Edinburgh came just a week after Italy had only narrowly lost to the Scots, 16-12, in Turin.

"I don't understand how we can change so much, one week to the other," said Brunel, in a comment that would have been echoed by many Italy fans.

Italy have tended to be known for playing forward-dominated rugby but in fly-half Tommasso Allan and centre Michele Campagnaro they are starting to develop inside backs who can pose a threat to opposition defences.

The closest they came to a last eight spot was in 2007, when only an 18-16 defeat by Scotland denied them.

They could yet have a 'spoiling' role at the World Cup, being sufficiently -- and legitimately -- aggressive to tire our or injure opponents ahead of more significant matches, but it's hard to see how Italy make it through to the quarter-finals.

If they do, it will be one of the greatest achievements in their rugby history.

Italy open their World Cup campaign against France at Twickenham on September 19.
Source: AFP