Pazzini and Criscito out of Italy squad
Pazzini, who fought through the pain to play in Inter Milan's 3-0 defeat by Napoli on Saturday, could be fit for Italy's final qualifier against Northern Ireland on October 11 but left-back Criscito is out of both matches with a groin strain.
"He [Pazzini] is suffering pain again in his heel," national team doctor Enrico Castellacci said on the federation's website.
"We will try to get him ready for one of the two games, that is the one against [Northern] Ireland."
Giuseppe Rossi, who has teamed up in attack alongside Antonio Cassano in Cesare Prandelli's recent line-ups, is also doubtful for the trip to Serbia.
"He's got the same problem he had in Spain," said Castellacci. "It's too early to say if he will be fit for Friday."
Mario Balotelli and Sebastian Giovinco, along with Cassano, are the remaining strikers in the Azzurri squad.
Italy, eight points clear in the group, have already qualified for Euro 2012.