Upon graduating college in 1998, Prideaux joined the
Seattle Sounders of the
A-League. He excelled for the Sounders, registering two goals and ten assists while leading the team in minutes played. Prideaux's performance in the A-League attracted the attention of MLS, and he signed with the
Kansas City Wizards for the 1999 season; he played in 15 games, starting 8, registering one assist. In his second year with the Wizards, Prideaux seized a starting role, starting all 31 of the games he played in, and helped lead the Wizards to an
MLS Cup, playing a part in one of the best defenses in the league's history. Prideaux played with the Wizards one more season, before being traded to
D.C. United for
Stephen Armstrong prior to the 2002 season. Prideaux started 53 of 55 games he played for D.C. in 2002 and 2003, but had his starting position challenged in 2004 with the emergence of
Josh Gros, and a tactical shift that led the team to play a 3-5-2 formation more often. Nevertheless, he started 16 games, and was a useful role player for the club. In 2005, he resumed his regular role, starting 28 of 29 games, but served primarily as a backup in 2006, playing in only 9 matches after suffering a knee injury. While in D.C., Prideaux coached the NCSL division 1 Arlington Warriors, and led them to great success in Metro area league. Prideaux has yet to score a goal after eight years in MLS and currently holds the record for most matches played without scoring having succeeded
Nick Garcia after the latter finally scored his first in June 2006. On December 15, 2006, D.C. United traded Prideaux to the Colorado Rapids in exchange for two draft picks. Prideaux was waived by the
Colorado Rapids on March 4, 2008, and was picked up by the
Chicago Fire in the MLS Waiver Draft. Prideaux announced his retirement from MLS on June 9, 2009, effective at the end of the season. ==Coaching career==