The two-time Big Ten player of the year at quarterback said he's been monitored running four miles during a practice.
''Oh my God,'' he said Sunday during Ohio State media day. ''I can barely run a mile playing quarterback.''
Coach Urban Meyer said Miller will have to adjust to the wear and tear on his ankles and knees from not just running but making quick starts, stops and cuts.
''As a receiver you line up and you run for two hours,'' Ohio State coach Urban Meyer said. ''As a quarterback you don't run. You run for maybe four or five minutes at practice and you're doing other things.''
Miller underwent a second surgery on his throwing shoulder nearly a year ago and redshirted the 2014 season when the Buckeyes won the national championship.
His decision to switch positions narrowed Ohio State's quarterback competition to two: J.T. Barrett and Cardale Jones, who helped Ohio State win its final three games after Barrett broke his ankle in the season-finale against Michigan.
Miller said his torn labrum is still not 100 percent and his shoulder just can't stand up to the rigors of playing quarterback. But Miller was one of the best running quarterbacks in college football and his speed and elusiveness should make him a good fit at H-back.
He said he's been lining up all over the field in practice. Meyer talked about the double-pass play the Buckeyes were practicing with Miller.
''It's just like playing a video game,'' Miller said. ''They just put anybody anywhere.''
Miller might even get a chance to return punts.
''He's been doing great,'' receiver Michael Thomas said. ''Every day he's making progress as a receiver. He's shown that he's dedicated. The sky's the limit for him at that position.''
As for the surgically repaired shoulder: ''I went up for a ball (Saturday),'' Miller said. ''The guys hit me in my legs. I fell on my upper body. I felt pretty good.''
Their absences could also lead to five-star freshman quarterback Torrance Gibson from Plantation, Florida, seeing the field as a wide receiver.
With a logjam at quarterback, he also voluntarily switched positions last week.
''He's a kid that runs fast and is a really good guy,'' Meyer said.