Simplify the following text for a Grade 9 native English-speaking person.
Original: ; 2006 For the 2006 season the team signed Nick Heidfeld from Williams to be their lead driver , while 1997 World Champion Jacques Villeneuve had his existing Sauber contract confirmed .
Simplified: ; 2006 For the season the team signed Nick Heidfeld from Williams to be their lead driver , and retained Jacques Villeneuve as the second driver .