Valladares started his career at local club Real Comayagua, and made his professional debut in 1997 with F.C. Motagua.[2] In 2003, as a third-choice keeper{Clarify} at Motagua he entered as a striker in an injury-plagued derby with Olimpia. He scored a header and played few more games as a striker before returning into goalkeeper duties with Motagua and then Olimpia.
After for so many years playing for Olimpia, on 7 November 2016 he announced that he would officially end his career, then after losing to Motagua in the semifinals of the Apertura 2016 on 4 December 2016, he officially retired from playing after 19 years since he began his career with Motagua in 1997.[3][4]
Valladares has been the first-choice goalkeeper for his country for over 10 years and became the third Honduran to reach a century of caps,[10] after record cap Amado Guevara and Honduras' top goalscorer of all time Carlos Pavón.[11] He was an instrumental figure behind Honduras's qualifying run to the 2010 FIFA World Cup finals and played in all three games in South Africa, conceding 3 goals against Chile (0–1) and Spain (0–2) before keeping a clean sheet and earning the Man of the Match award in the team's final game, against Switzerland.
His nickname in the Honduras squad is The Secret due to his shy personality away from the field. In 2010, he succeeded Amado Guevara as the captain of the Honduras national football team.
In 2011, he won the award for "Best Goalkeeper in the 2011 CONCACAF Gold Cup." In the same tournament he won the award for the 3rd as well as the 4th best save.