The Wildcats had an 11 p.m. curfew on Wednesday, but Roberson was found to be out of his room at the Scottsdale (Ariz.) Plaza Resort at 4:30 a.m.
Kansas State athletic director Tim Weiser told ESPN that coach Bill Snyder will determine whether Roberson will start or even play against Ohio State.
Roberson was not with the Kansas State players at a pep rally Thursday afternoon, where 14,000 K-State faithful gathered at the Well Fargo Arena on the Arizona State University campus, according to The Associated Press.
Faced with the possibility of his star quarterback not playing, Snyder told fans that the Wildcats will "need to show great courage, great perseverance and be tremendously focused on the task at hand."
"That might not be easy tomorrow evening," Snyder said.
The senior from Baytown, Texas, needs 57 yards to become the third Division I player to rush for 1,000 yards and pass for 2,000 in a season.
Information from The Associated Press was used in this report.