Giancarlo Abete, the president of the Italian Football Federation, is behind Prandelli despite watching Cassano net four times in seven Serie A games this term.
Cassano also has an impressive scoring record with 10 in 35 games for the national side.
Italy are top of Group B following a 3-1 win over Armenia on Friday. They meet Denmark at the San Siro in Milan tomorrow night.
“The exclusion of Cassano is down to the tactical decisions of the coach," said Abete. "The coach wants to look at new players.
“Spain, for example, changed half of their side after they won the European Championship and did the same after winning the World Cup.
“We don’t have any indispensable players, apart from Juventus’ Andrea Pirlo. There are other first team players, but they are all approachable ones.”
- Italian Football Federation