Dudar began his career in the youth ranks of Velez Sarsfield and made his First Division debut in 2000. During his debut season he was named Rookie of the Year by the Asociacin del Ftbol Argentino. In over four years at the Buenos Aires club, he made 63 appearances and scored 5 goals. For the 2003/04 season he was loaned out to Independiente and was a regular starter appearing in 19 matches and scoring one goal. For the next few years he was loaned out to Banfield, Caracas, and Libertad. In 2005, he signed with Carabobo in Venezuela’s top flight and remained at the club for one year before returning to Argentina. He signed with Tigre for the second half of the 2005 season and appeared in 15 games. His play with Tigre drew the attention of top Brazilian club Vasco da Gama. He joined Vasco in 2006 and appeared in 34 official matches for the club.
In 2007, he left for Europe, joining FC Chiasso of the Swiss Challenge League and appeared in 14 matches scoring 3 goals. He returned to Argentina in 2008 playing for Olimpo de Baha Blanca. His prior experience in Switzerland led to his signing with Swiss side AC Bellinzona in the second half of the 2008-09 campaign, where he played in 16 matches and scored two goals. The following season, he joined BSC Young Boys. In his first year with Young Boys he was named the Swiss Golden Player as the league’s top defender. He started in 31 matches that season scoring one goal. Dudar’s second season with Young Boys was cut short as he was placed in a medically induced coma after suffering a severe head injury on 12 September 2010, when he accidentally clashed heads with teammate Franois Affolter. He was successfully woken up a day later.