Frentzen retired at the end of 2003 .
Sauber rehired Frentzen to partner Giancarlo Fisichella , but Frentzen only scored 12 points compared to Fisichella 's 22 In 2005 Frentzen stayed at Sauber , this time with former world champion Jacques Villeneuve as his teammate .
Frentzen retired at the end of 2003 and Sauber rehired him to partner Giancarlo Fisichella , but he only scored 12 points compared to Fisichella 's 22 In 2005 he stayed at Sauber , this time with former world champion Jacques Villeneuve as his teammate .