Marseille - Tour de France team Cofidis suspended Frenchman Remy Di Gregorio over doping allegations, the team announced on the race's first rest day on Tuesday.
Di Gregorio was arrested following a police raid at his team's hotel in Bourg-en-Bresse, several miles outside Macon in eastern France where the race will resume on the 10th stage on Wednesday.
A team statement said: "We have just learned that one of our riders, competing at the Tour de France, has attempted to resort to doping substances to improve his performance.
"At the current time, we have very little information about the facts of the case.
"However the suspicion on the rider concerned, Remy di Gregorio, leaves us with no choice but to hand down the strictest possible sanctions.
"Remy di Gregorio is therefore immediately suspended, provisionally, while we await more ample information on the case.
"If the suspicions are confirmed, he will be sacked on the spot - in accordance with the stipulations in his contract and in line with the ethical policy of the team."