Riveros started his career in his hometown club Colón de J.A. Saldivar and then moved to other Paraguayan teams such as San Lorenzo and Tacuary before playing for Libertad.
On July 12, 2007 he signed for the Mexican club Cruz Azul.
On 11 May 2010, Riveros signed for Sunderland on a three-year-deal. He has said "The league is very competitive and I look forward to being very successful with Sunderland. The Premier League is the best league in the world and Sunderland are a very big club with many passionate supporters. I look forward to meeting them." He will link up with Paraguay national team-mate Paulo da Silva.
He made his Premier League debut on the 14th August 2010 against Birmingham City coming on as a sub in the opening game of the season. However, Riveros quickly fell out of favour at Sunderland making just a handful of further appearances. He did however manage to score his first goal for the club on the final day of the season in a 3–0 win over West Ham United.