Milan have recruited heavily this summer, spending big sums on the likes of Bonucci, Andre Silva, Andrea Conti and Hakan Calhanoglu in particular, and Maldini even suggested he was slightly surprised the club managed to prise Bonucci away from rivals Juventus.
"I don't know what happened. It's certainly difficult to find [good] centre-backs and Bonucci's one of the best. Bonucci's certainly an excellent buy," the five-time European champion told Sky Italia (Football Italia).
"It seems a bit early for them to go for the Scudetto, but they'll fight for a place in the Champions League," he also said of his former club.
Milan haven't finished higher than sixth in Serie A since 2012/13, finishing as low as 10th in 2014/15, while two Supercoppa Italianas are the only (minor) trophies to make their way to the San Siro since league success in 2011, six long years ago.
Yet while only a second Serie A title since 2004 remains the ultimate goal for Milan under their ambitious new ownership, Maldini feels that Juventus will continue to be the team to beat for the time being, that's despite losing a key player in Bonucci.
"First of all, we have to say the transfer window is still open and that we have to wait until it's closed before we can pass judgment on any team," suggesting Juve will yet strengthen further.
Maldini also went on to describe the Bianconeri, Italian champions in each of the last six seasons - an unprecedented level of domestic dominance, as a "proven team".