Valdes has been frozen out at Man United following a falling out with Louis van Gaal.
The former Barcelona keeper, who has been training with United’s youth teams this term, will likely never feature for the club again.
Herrera backed his compatriot to bounce back at a different club when the January transfer window comes around.
“I think he’s still capable to come back and be one of the best goalkeepers in the world. He’s working very hard to do that. As for the relationship he has with the manager, that’s between him and the manager and not my place to talk about,” Herrera said.
“I can only talk about him as a teammate and a friend of his, and I’m sure he’ll return to how he was before. I’m sure he’ll find another team in January and will be able to show who he is, because he’s training, he’s training for himself.”
Valdes has been linked with the likes of Newcastle United in recent weeks and a move would benefit all parties. The keeper is too good not to be playing while United would get an unhappy player off their books.