Frasnelli started for the first time in December 2000 in Brusson in the sprint in the cross-country skiing world cup and finished the race in 42nd place. He won his first World Cup points in February 2001 with ninth place in the sprint in Asiago . Frasnelli achieved his best individual result with fourth place in the sprint in Davos in February 2006. In the team sprint, he and Cristian Zorzi achieved his only World Cup victory in March 2006 in Sapporo ; In January 2010 in Rybinsk , he and Fabio Pasini once again reached a World Cup podium in this discipline with second place. Frasnelli competed three times in the Tour de Ski . With sixth place in 2010 and fifth place in 2011 at the prologue in Oberhof , he was able to place twice in the top 10 of a stage, but only finished the stage race in his first participation, in which he came in 61st place.
Frasnelli also started for Italy at the Winter Olympics in Turin and Vancouver . He finished sixth in the sprint in 2006 and reached 30th place four years later in Vancouver .
After the 2013/14 season, Frasnelli did not contest any international races.