Quote Originally Posted by seb_sh View Post
It can be a number of things. Tanak was seen testing his new co-driver before it was announced but also Ogier was tested with Camilli's co-driver several times. The reason can range from preparing to change to having a backup to simple unavailability due to personal reasons.
if you research nolan, he has done next to no co-driving, so he is not a legitimate replacement, and from killarney, so likely nagel just recommended him in his absence. that took all of 1 min google research, but probably event that is too much effort for most rumour mongers.