Lance Armstrong has pulled out of tomorrow's 2010 Milano-San Remo race, citing acute gastroenteritis.

Team RadioShack told Roadcycling.com that the seven-time Tour de France champion would be replaced by Fumiyuki Beppu.

"It would not be very intelligent to let him start in a race of almost 300K, while not being healthy," team director Johan Bruyneel said in a statement earlier today.

The Milan-San Remo is the opening single-day classic of the cycling season, and at 298 kilometers (185 miles) is one of the longest of the year.

Armstrong finished 125th in San Remo last year in one of his first races back from three years in retirement. Before retiring in 2005, he raced the Milano-San Remo six times and never won.

Armstrong is set to face his fierce rival and former teammate Alberto Contador next week at the Criterium International taking place on Corsica this year.

Armstrong is also now scheduled to ride in next month's 2010 Circuit de la Sarthe in France as part of his preparation for the Tour de France. It will be his fourth appearance in the race, which will take place from April 6-9.

Armstrong rode the Circuit de la Sarthe in 1999, 2001 and 2003, winning a stage three months before his first Tour win in 1999.

Watch 2010 Milan-San Remo video highlights right here on Roadcycling.com - so stay tuned to Roadcycling.com.