Answer
Antônio Pizzonia replaced Ralf Schumacher at Williams in 2004. Schumacher had been with Williams since 2000, and had won the World Drivers' Championship with the team in 2002. However, he had been struggling with injuries in 2003 and 2004, and was eventually replaced by Pizzonia. Pizzonia did not have the same success as Schumacher, and was only able to score one point in the 2004 season.