The world and European champions are looking to add the Olympic football title to their list of honours 20 years after their only previous success at the Games in Barcelona, but Herrera is aware that there are a number of strong sides capable of challenging for medals.
He told Marca: "The objective is to start well and play well. To win a medal would be fantastic and the gold would be incredible, especially given how long it has been since Spain has been at the Games.
"However, we always respect the opponents because at this level anyone can cause you problems.
"Brazil is the favourite and Great Britain as hosts and with the team they have are too. Then there is Mexico, Uruguay, the African sides...we want to be in this group (of favourites) but we have to win on the pitch."