The masked 'Psychosocial' rockers' percussionist - whose real name is Shawn Crahan - was asked during a panel at Pollstar Live! in Los Angeles whether the two huge groups would ever join forces for a festival.
As reported by Blabbermouth, he responded: "I ask myself, does Slipknot want to play next to the Foo Fighters? The answer is no, because my kids don't want me to do that.
"If we play alongside the Foo Fighters, we are going to get new fans, I agree with that. I love that. But I'm worried about the kid that won't come to the show, because we're playing with the Foo Fighters. He wants to know why we're not playing with Nine Inch Nails."
The Clown added that Slipknow's fan base isn't shy about voicing their opinions, and they want to continue to be there for them as they use the band as an outlet to deal with - and escape from - any issues they might be facing.
He explained: "Those kids tell all of us what they want. So, don't try to figure out ways of how to combine things for the new fan.
"I don't need the new fan, I need the fan that has anxiety, parents are getting divorced, social problems, gender problems - I need them to come to the ultimate show. And they're going to get that at Knotfest."