Italy team doctor Enrico Castellaci says the striker is suffering from some "teething problems" in his legs as he battles to be ready to face England on June 14
The 23-year-old is set to be a crucial player in Cesare Prandelli's plans for the finals in Brazil this month, particularly after Giuseppe Rossi's omission from the squad.
Veteran Antonio Cassano and the internationally inexperienced trio of Alessio Cerci, Ciro Immobile and Lorenzo Insigne the alternatives in attack and the Azzurri will be desperate to ensure Balotelli is fully fit.
Italy team doctor Enrico Castellaci has revealed the former Manchester City man has been struggling with muscle fatigue during the pre-tournament camp in Coverciano, meaning he could potentially be a doubt for the clash with England in Manaus on June 14.
"He's having a few teething problems with his flexors and adductors," Castellaci is quoted as saying by La Gazzetta dello Sport.
"He was struggling a little when he arrived at Coverciano. They've [his muscles] been overworked these last few days and that's affected them."
Balotelli, who struck four times in Italy's World Cup qualifying campaign, scored 18 goals in 41 appearances for Milan in the 2013-14 campaign.