Director Zack Snyder announced on Friday (23Aug13) he wants the Good Will Hunting star to play the Caped Crusader in a sequel to Superman movie Man of Steel.
The surprising news sparked fury among many fans of the franchise, and an online petition to reverse the move had attracted more than 80,000 signatures by Wednesday (28Aug13).
Now Affleck's close pal Damon has spoken out to silence critics, insisting the role is not a taxing one and is well within his friend's "skill set".
He tells The Times of India, "I think it will be great. It will be terrific. I know there are a lot of people grousing on the Internet. I just think it's kind of funny. You know, he's not playing King Lear. It's Batman! Certainly within his skill set.
"If anybody saw Argo or The Town and all the work he's been doing lately, it's way more nuanced and interesting and way more difficult than Batman! Batman just sits there with his cowl over his head and whispers in a kinda gruff voice at people.
"Bruce Wayne is the more challenging part of the role, and Ben will be great at that... But it's safe to say I won't be Robin."