Robson, who retains close ties with United as a global ambassador, thinks Ferguson will get a say in who replaces him.
"The favourites are up there," Robson said.
"Mourinho gets mentioned all the time and David Moyes has been mentioned for quite a time.
"I think the boss gets on really well with both of them and I am sure the boss will have had a say in where the club do go next.
"The one thing I always believe with Manchester United, and that is why I am pleased to be involved with them, is that they do get a lot of decisions right and I am sure that they will get this one right."