The Italian defender made his way back to Juventus earlier this summer after just one season at San Siro, but the Rossoneri have got a new defender in Mattia Caldara, while Gonzalo Higuain has also joined the club.
Abbiati has hinted that broken promises are probably to blame for Bonucci leaving, and also admitted surprise over the club's capture of Higuain.
“Higuain? I am surprised Juventus did this operation, he is the goalscorer AC Milan were looking for," he told La Gazzetta dello Sport.
"Bonucci? Probably he was made promises that were not kept, but Leo helped Romagnoli to improve. Hard work is always rewarded, no doubt.”
Milan have faced many challenges since Silvio Berlusconi sold the club in 2017, but Abbiati claims to be impressed with the way Gennaro Gattuso has handled things at squad level.
“The situation was a bit confusing too," he added. "People pretended that the organization was perfect but it wasn’t like that. I am not surprised of how things ended up, my point of reference has always been Gattuso. What he did was incredible, he motivated the players and he entered their minds."
There was also praise reserved for Gianluigi Donnarumma, who has somewhat surprisingly remained at San Siro throughout the turbulence, despite being wanted by many other top clubs in Europe.
“Donnarumma? He was one of the few people to be brave enough to go against Raiola," Abbiati declared.
"He has always acted for the club’s good. There are many games next season and both Donnarumma and Reina will have game time.
"Now he will train with another goalkeeper coach. Magni did a great job. He took Donnarumma to the level he is now, but in the last year he has not improved.”