 Complete the following phrase:  At a test held at the Autodromo Nazionale Monza, Schumacher suffered a high-speed accident where he sustained a concussion. He was taken for a precautionary check at the circuits medical centre before he was transferred to San Rafaele hospital. Although he had participated in the events first qualifying session, Schumacher decided to withdraw and his place was taken by Williams test driver Marc Gené. He returned for the United States Grand Prix where he retired having suffered an accident resulting from his car sliding on a wet track surface. At the season finale in 