Sevilla tested positive for hydroxyethyl starch during the Vuelta a Colombia in August 2010 but was not formally sanctioned by the Spanish Cycling Federation (RFEC) until September of last year. When the RFEC then decided to hand Sevilla a six-month suspension, the UCI announced its intention to appeal the matter to CAS.
Hydroxyethyl starch is a blood plasma volume expander that can be used as a masking agent for EPO. The specified substance is illegal only if used intravenously, and Sevilla blamed his positive test on the treatment he received in a Colombian hospital following a crash. The RFEC took this explanation into account when handing him the reduced suspension.
Ezequiel Mosquera also tested positive for hydroxyethyl starch in the autumn of 2010, after finishing second at the Vuelta a España, as did his Xacobeo Galicia teammate David Garcia. Both men were ultimately handed two-year bans.
Sevilla raced for much of the 2011 cycling season for Gobernacion de Antioquia - Indeportes Antioqua, including the Vuelta a Colombia, Tour of Utah and USA Pro Cycling Challenge before beginning his suspension on September 14 last. His ban expires on March 12, a little over one week before the CAS hearing that will decide whether or not it is to be extended.
In 2006, Sevilla was fired by T-Mobile following his implication in the Operacion Puerto blood doping scandal, although he never served a suspension for the matter.