The Serie A champions' head coach has said that Alexandre Pato is currently sitting in pole position to partner Zlatan Ibrahimovic up front against the Catalans
Cassano impressed for Italy's national side earlier this month and helped Milan to a 2-2 draw against Lazio at the weekend by scoring once and setting up another goal, but Allegri feels that Alexandre Pato is the better option at Camp Nou.
"Cassano put in a superb performance in the game against Lazio, but Pato is the favourite to start alongside Zlatan Ibrahimovic against Barcelona because of his specific characteristics," Allegri was quoted as saying by La Repubblica.
The Milan coach was full of respect for his side's upcoming opponents, but stressed that the San Siro side have plenty of quality as well.
"We have a lot of respect for Barcelona. They play some of the best football, but we shouldn't forget that we have great players, too," he said.
"We have to be very alert at the back and up front. We can't afford to be careless."