Italy captain Sergio Parisse has returned to training ahead of the Azzuri's clash against Ireland on Sunday.
The Stade Francais number eight eventually joined Italy's World Cup camp on Tuesday but will have to pass two fitness tests in order to make the lineup to face Joe Schmidt's side.
"He hasn't been training for three weeks and will now be trying to play a massive match on Sunday," team doctor Vincenzo Ieracitano told reporters on Tuesday.
"He's happy to be here and confident he will be able to play. He has been continuing the physiotherapy that he was undergoing in Paris. This afternoon he will have physiotherapy to get him over his journey from Paris, and then he will join in training in the gym and on the pitch.
"Tomorrow he will definitely train with the rest of the squad, then on Thursday he will go through a fitness test in the gym. And if that goes well we will see how he gets on in training and then we will have another check to see if he can play."
Italy sit in third spot in Pool D ahead of their tie with Ireland at the Olympic Stadium.