Mendenhall, the Big Ten Player of the Year, made his final case as a pro prospect in the Rose Bowl, where he gained 155 yards rushing and added 59 receiving yards in the Fighting Illini's loss to Southern California.
In 2007, Mendenhall rushed 262 times for 1,681 yards -- an average of 6.4 yards per attempt -- and 17 touchdowns.
Mendenhall's college coach, Ron Zook, told the Chicago Tribune that he expected he would turn pro.
"We all know he's a first-round talent," Zook said, according to the newspaper.
The Tribune also reported that his mother, Sibyl, said a news conference was planned for Thursday at Niles West High School, his alma mater.
Joe Schad covers college football for ESPN.