The Uruguay international was a key figure at the club in 2012-13 and Buffon has acknowledged that the 26-year-old's exit could have been a big blow for the Stadio San Paolo side had the club not brought in an adequate replacement.
However, he has stressed that the Partenopei responded well to Cavani's exit by signing Gonzalo Higuain from Real Madrid.
"In general, [Rafa] Benitez's squad is stronger and more experienced than last year," Buffon was quoted as saying by Corriere dello Sport. "The departure of Cavani could have had an impact if they had brought in someone of lesser quality. The difference is not felt when you bring in someone like Higuain, though.
"He has different abilities, but is of equal quality."
Buffon then went on to discuss this weekend's Serie A clash against Napoli and highlighted the importance of the encounter as well as praising president Aurelio De Laurentiis for restoring the club to its former glory.
"Games between Napoli and Juventus had lost some of its prestige after the days of Diego Maradona and Michel Platini," he continued. "We have both returned to the top, though, and it's a beautiful match once more.
"Aurelio De Laurentiis deserves credit for Napoli's re-emergence. He has done some great work. I hope that it will be a great evening."
Juventus and Napoli sit joint second in the Serie A table at the moment with 28 points from 11 games.