Contreras won the Best Spiker award at the
2001 NORCECA Championship, and Best Scorer at the
2005 version. At the
2007 NORCECA Championship, Contreras was awarded Best Receiver, and his national team finished in 5th place. Contreras won the Dominican Republic "2007 Volleyball Player of the Year". In mid-June 2012, the Poland club
Zaksa Kędzierzyn-Koźle announced his joining for the 2012–13 season. Contreras won the bronze medal in the
2012 Men's Pan-American Volleyball Cup playing with his national team, and also won the Best Receiver and Best Server awards. Contreras led the Technocrats to the title of the 2013 Caribbean Volleyball League, also winning the Most Valuable Player, Best Scorer, Best Spiker, and Best Server awards in the Trinidad and Tobago-based tournament. He then joined the Brazilian club Funvic Taubaté. In August 2014, Contreras announced that he would retire from the national team after the
2014 Central American and Caribbean Games. At these games, the Dominican Republic won the gold medal for the first time, and Contreras was awarded the Most Valuable Player, Best Outside Spiker, and Best Scorer. ==Clubs==