Allen played for the Indianapolis Colts, appearing as a kick returner.
He attended Damien High School in LaVerne, California, where he was on the football and track and field teams.
In the 1998 season, Allen appeared in all 11 games as a true freshman, recording four starts.
The Cardinal won the PAC-10 Conference and faced Wisconsin in the 2000 Rose Bowl, losing 9-17.
[3] As a junior in the 2000 season, Allen split running back duties with Kerry Carter.
Allen led the team in rushing with 174 attempts for 899 yards and four touchdowns.
He missed the entire 2002 NFL season, which he spent on the Colts' injured reserve list.
He underwent a second knee surgery prior to the season, and remained on the practice squad for the remainder of the year.