RadioShack team leader Lance Armstrong has had a setback to his racing schedule, with stomach problems forcing him to pull out of the Circuit de la Sarthe in France.

Today would have given the American a chance to once again test his time trial form thanks to a 6.7 kilometre afternoon time trial in Angers, but he has not started the morning road race and is out of the event.

Armstrong first indicated that there could be problems yesterday when he referred to illness amongst the team which competed in Belgium on Sunday. “6 of the 8 guys from our Flanders squad are down and out w/ a stomach bug. #hopingimlucky,” he wrote on Twitter.

Several hours later, things had taken a turn for the worse. “Not so lucky I guess. Sicker than a dog now. This sucks.”

Confirming the news, his RadioShack team issued a statement this morning. “Armstrong came down with a viral intestinal infection after the conclusion of Stage 1. He will return to the US as soon as his condition allows,” it read.

“Many riders from different teams caught the virus last week in Flanders. Five from the eight Team RadioShack riders who participated in the Tour of Flanders came down with the virus including Geoffroy Lequatre, Dmitriy Muravyev, Gregory Rast and Sébastien Rosseler. Also Team Manager Johan Bruyneel and a soigneur are affected.”

Team director Alain Gallopin said that the remaining members of the team would try to do something in the days ahead. “This is not the right moment, but it is never a good moment. Though we have only four riders left in this race, we will try to win a stage. Tiago Machado and Yaroslav Popovych are in good shape. Let’s hope Popo will not get sick. He too was in Flanders last week.”

Popovych was on the attack yesterday and ended the day leading the mountains classification. He has 14 points, compared to the eight held by Yury Trofimov (Bbox Bouygues Telecom).

Media reports yesterday morning confirmed that Armstrong had dropped Amstel Gold, Fléche Wallonne and Liège-Bastogne-Liège from his schedule. That reshaped plan of races may now well be rejigged once more.

“As far as Lance Armstrong is concerned, maybe we will have to change his program again,” said Gallopin. “That’s work for the coming days. Lance was really keen on performing well, especially in the time trial of Wednesday afternoon. He showed his growing condition in the Tour of Flanders, where he came in with the first group sprinting for the fifth place.”

The Circuit de la Sarthe continues this morning with a 97 kilometre leg from Varades to Angers.

The leader’s jersey is held by the Spaniard Luis León Sanchez (Caisse d’Epargne), who timed his finishing sprint perfectly to beat Marko Kump (Adria Mobil), Anthony Ravard (Ag2R La Mondiale), Sébastien Chavanel (Francaise Des Jeux) plus the rest of the main bunch into Varades.

Sanchez is a strong time trialist and could well defend the jersey this afternoon.