BALTANAS, Spain (AP) — Lance Armstrong will have surgery after breaking his collarbone Monday during a race in Spain.

"I'm alive!" the seven-time Tour de France champion wrote on his Twitter feed. "Broken clavicle (right). Hurts like hell for now. Surgery in a couple of days. Thanks for all the well wishes."

The 37-year-old American cyclist was knocked off his bike during a pileup in the first stage of the Vuelta of Castilla and Leon race.

The injury has jeopardized his participation in upcoming races. Armstrong was scheduled to compete in the Giro d'Italia from May 9-May 31 and the Tour from July 4-26.

"For the Giro it's a very big problem," he said as he left Valladolid University Hospital. "For now, the biggest problem is just the pain."

Armstrong won seven straight Tours from 1999-2005 before retiring. He returned after 3½ years, and at 37 was hoping for another triumphant ride through Paris.

"The crash has put my upcoming calendar in jeopardy, but the most important thing for me right now is to get back home and rest up and begin my rehab," he said in a statement.