Camoranesi was included on Tuesday in the 23-man squad for the finals in South Africa but can be replaced before the first match of the June 11-July 11 tournament.
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"I could take a 24th player to South Africa. In the next few days we will see how Camoranesi is," Lippi told reporters before adding that Cossu was the likely candidate having just missed out on the final squad.
Italy face Mexico on Thursday in the first of two friendlies before meeting Paraguay in their Group F opener in Cape Town on June 14.
Lippi said he would probably play his strongest side against Mexico in Brussels although centre back Giorgio Chiellini may be rested because of a minor niggle.
The coach surprised pundits by selecting striker Fabio Quagliarella in his squad instead of Marco Borriello or Giuseppe Rossi.
Lippi said he picked players who were more versatile and Quagliarella is now keen to pay him back.
"It's happened often in my career. When people say I'm dead I always bounce back. Perhaps this is my true strength," the Napoli striker said at Italy's Alpine training base in Sestriere.
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