Cristian Moreni's positive test for testosterone also prompted the withdrawal of his entire team.
The case of the Italian rider is fueling the deep sense of crisis already hanging over the race and the sport as a whole. It comes one day after star rider Alexandre Vinokourov and his entire team were sent home after the Kazakh rider tested positive for a banned blood transfusion.
French riders staged a protest at the start of today's 16th stage to express disgust at the repeated doping scandals that have left cycling's credibility in tatters.
And the vice president of the World Anti-Doping Agency suggests that the sport could be withdrawn from the Olympics.