RadioShack spokesman Philippe Maertens said "the main reason" Armstrong won't ride in the one-day race is he wants to join son Luke for the Pinewood Derby. But Armstrong also feels his form is good enough for him to train in the United States.

Maertens said Armstrong will race in next month's Tour of California, then decide whether he will compete in either the Dauphine Libere or the Tour of Switzerland in June.

Armstrong is currently riding in the four-day Circuit de la Sarthe in northwestern France. He finished 24th in Tuesday's first stage behind leader Luis Leon Sanchez of Spain.

Armstrong and three-time defending champion Levi Leipheimer will anchor Team RadioShack when the Tour of California begins May 16.

The race is moving from February to May this year.

The eight-day event starts in Northern California and ends more than 800 miles later in Thousand Oaks, outside of Los Angeles.

Tour of Flanders winner Fabian Cancellara and Tour de France runner-up Andy Schleck will ride for Team Saxo Bank, while American George Hincapie rides for BMC Racing.