One of the best defensive players to come out of El Camino College, Riddle was a team captain and named team MVP in his sophomore season in 2002. He is currently ranked No. 3 in ECC history with 19 career sacks and is tied for fourth all-time in single-season sacks with 11 in 2002. Riddle was an All-Conference selection in 2002 as well as a Third-Team J.C. All-American. Riddle would continue his collegiate career at Cal and is still the single-season sack record holder in Bears history with 14.5 sacks in 2004. He is ninth all-time in career sacks with 21.0. He earned First-Team All-PAC 10 and Second Team AP All-American honors. Riddle was selected by the Oakland Raiders in the sixth round of the 2005 NFL Draft and went on to play 17 career games in the NFL over two seasons.