Alberto Aquilani has withdrawn from the Italy squad after picking up a head injury in the 3-0 win over Estonia.
The midfielder was replaced in the first half of the Euro 2012 qualifier in Modena on Friday evening.
Aquilani, who has just completed the season on loan at Juventus from Liverpool, was sent to hospital for tests but returned with the rest of the squad to Florence late last night.
With Tuesday's game against the Republic of Ireland only a friendly, he has been allowed to return home to rest.
Prandelli initially named a 25-man squad for the two games, but also lost Thiago Motta and Mario Balotelli to injury.
The tactician did add to his squad this morning though by selecting Torino stopper Angelo Ogbonna.