At San Diego State, Underwood was named honorable mention All-Mountain West Conference his junior and senior seasons.
While at San Diego State, Underwood help create an Aztec Defence with Kirk Morrison of the Oakland Raiders, Matt McCoy of the Tampa Bay Buccaneers, Heath Farwell of the Minnesota Vikings, and Jonathan Bailes.
Backing up his fellow rookie & teammate, Nick Collins, Underwood appeared in all 16 regular-season games during the 2005 season.
Misfortune hit Underwood when he tore two ligaments in his right knee in a preseason game against the San Diego Chargers.
[6] After spending over two months as a free agent, Underwood was re-signed by the Packers on November 25 when defensive tackle Colin Cole was placed on injured reserve.
The following week, on November 30, Underwood was released again when quarterback Craig Nall was re-signed due to an injury to Brett Favre.