Michael Keaton proved to be a great villain for Spider-Man: Homecoming, and with the sequel in the works, everyone is curious on who will be the big bad for the sequel. As it turns out, Matt Damon was approached for a role.
According to Jeff Sneider from Meet the Movie Press, Damon was asked to play an unidentified villain in the Homecoming sequel, but he ultimately passed on the part. With a lot of people speculating that the main villain would be Kraven the Hunter, I'm guessing that Damon would have been up for a supporting role and would come back as the villain for the third movie. People might have guessed that he was up for Kraven, but with PC culture these days, the movie would probably look for a legit Russian actor to play the character.
I'm guessing they could have Damon play Norman Osborn (Green Goblin) or maybe another Professor Connors (Lizard). Sony has also yet to show us Mysterio so that role could also be up for grabs.
What's funny is, Damon is already part of the MCU in the form of a cameo as an Asgardian theater actor playing Loki. Having him in Spider-Man in a different role would surely muddle up the continuity, but I would certainly like to see him in a larger role in the future.
The Spider-Man: Homecoming sequel is set to come out July 5, 2019.