Joel Rosario will ride McKinzie in the Breeders' Cup Classic on Nov. 2 at Santa Anita, trainer Bob Baffert said on Wednesday.
Rosario will take over from Mike Smith, who had ridden McKinzie in all his previous starts.
McKinzie most recently finished second in the Awesome Again Stakes at Santa Anita behind Mongolian Groom.
Rosario has been the regular rider for another Breeders' Cup Classic contender, Yoshida, so he will need a new rider.