He played college football for the Kansas State Wildcats and was selected by the Denver Broncos in the second round of the 2003 NFL draft.
After racking up 38 tackles (six for a loss) and three pass break-ups, he was named the Big 12 Defensive Freshman of the Year.
On November 16, Pierce suffered a torn pectoral muscle and was subsequently placed on injured reserve, ending his season.
In 2004, Pierce was to battle Donnie Spragan and Jashon Sykes for the starting strong-side linebacker job.
However, Pierce suffered a sprained medial collateral ligament in August, losing his chance at the job.