Gerhart made his announcement Friday, saying his is dropping out of school immediately to prepare for the NFL combine next month and the draft. Gerhart could have stayed for a fifth year because he played just one game in 2007 because of a knee injury.
Gerhart ran for a school-record 1,871 yards and a nation-leading 28 touchdowns this past season. He won the Doak Walker Award as the nation's top running back and finished second in the Heisman Trophy race to Alabama's Mark Ingram in the closest vote ever.
Gerhart helped lead Stanford to its first bowl bid in eight years. The Cardinal (8-5) lost the Sun Bowl to Oklahoma.