What would happen in this situation (all star game)?

In the all star game the American League Manager and the National League manager are selected by the previous world series game. For example the Giants made it so Bruce Bochy will represent the National League. The chances of this happening are slim to none but what if they decided to fire the manager. I'll continue to use Bochy for example what if the Giants decided to let him go which would never happen but for the sake of the question, lets just say he was fired who would be the NL manager? Would the manager that replaced Bochy become the manager to represent the National League?