Italy trio Daniele De Rossi, Giorgio Chiellini and Ignazio Abate face a race against time to be fit for Thursday's Euro 2012 semi-final against Germany in Warsaw.
De Rossi and Abate limped out of Italy's quarter-final victory over England on Sunday with muscle problems while Chiellini missed that game with a hamstring injury.
Chiellini trained on Monday and tweeted that he hoped to be fit but Italy doctor Enrico Castellacci said he could not be sure with any of them.
"We're doing everything we can to get them ready," he said.
Leonardo Bonucci replaced Chiellini against England and could easly do so again while Italy have Thiago Motta who could come back into the side to replace De Rossi.
The problem lies with right-back Abate as the man who replaced him on Sunday, Christian Maggio was booked and is suspended for the semi-final.
If he doesn't make it then Italy coach Cesare Prandelli will have a difficult choice to make as he has no other right backs.
Either Bonucci or veteran Andrea Barzagli could play there but that would need Chiellini to recover to come back into the centre.
Otherwise Prandelli may choose to revert to a back three with wing-backs, playing Fabio Borini on the right.
But when he played a back three earlier in the competition he used De Rossi as a libero and he would need either the Roma midfielder or Chiellini to recover anyway to be able to play that system.