He had the following to say to ABC (via Digital Spy):
"Justice League could be great if done correctly," Cavill told ABC News.
"It's a very tough one to do because the DC comic heroes are all god-like in their power. So in this real world setting we're telling our story in, it's going to be tough to achieve that and it has to be done very delicately with a lot of thought. So, it won't be right away, I hope it's not anyway.
"It may take some time of building up other movies and other characters and introducing them together in one way or another. I think it would be great to do, but I don't think it's around the corner."