Former San Siro favourite Alessandro Costacurta says AC Milan would be in entirely different shape had they signed either Pierre-Emerick Aubameyang or Andrea Belotti.
There is speculation that unsatisfactory results against Chievo on Wednesday and champions Juventus at the weekend could see Montella sacked, with former boss Carlo Ancelotti among those linked with his role.
Milan's struggles have come despite an expensive overhaul of the playing squad in the transfer window, with more than €190 million reportedly spent thanks to the backing of new Chinese owners.
"With someone like Belotti or Aubameyang in attack, we would be talking about a very different Milan," the 51-year-old, a winner of seven Serie A titles and a five-time European champion, told Sky Sport Italia.
"It's pretty clear they lack a quality centre-forward because they do get crosses in and their strikers make a lot of mistakes in front of goal."