Raas began his career as a professional in 1975 with the famous TI- Raleigh team and finished it in 1985, after 115 victories. His greatest achievement was winning the road bike World Cup in the domestic Valkenburg, where he won in front of 200,000 spectators sprint against the German professional Dietrich Thurau 1979.
1984 January Raas crashed hard at the spring classic Milan-San Remo and pulled to significant injuries to the spine and internal organs. Although he later succeeded a few months of winning the ninth stage of the Tour de France, but he could never reach again his usual level. Raas therefore ended on May 28 in 1985, career.
After his playing career was in January Raas sports director of the team Kwantum, which he eventually formed the still successful team Rabobank after a few sponsors change. In 2003 he retired as athletic director from Rabobank.