Miller, the Broncos' star pass-rusher and the NFL's Defensive Rookie of the Year, was one of Tebow's staunchest supporters last season, when the popular but polarizing quarterback supplanted Kyle Orton as Denver's starter.
"I think everybody's mistaken if you think he's just going to go over there and be a Wildcat quarterback or a situational quarterback," Miller said. "The Tebow that I know is going ... to be able to compete for that starting job."
Miller likes Tebow so much, he advocated for the Broncos to hold on to the quarterback even after they signed Manning.
"It was pretty crazy because I felt like we already had our quarterback with Tim," Miller told NFL.com last week. "It was surreal. We went from having our quarterback to not having our quarterback to having our quarterback. I'm happy that we got Peyton but unhappy that we got rid of Tim."
The Associated Press contributed to this report.