I don't understand how anyone who has ever played actual football before could think that substituting one player would have a positive impact in a game where the entire offense is struggling. Especially when that one player is a freshman quarterback who hasn't played a single college football play, and has not played in an actual game in two years. There's a name for that: it's called quitting. If Brewester had pulled Weber and put MG in at QB it would have been an obvious, sybolic, self-serving move ... but of no use in actually winning the game. And that's the whole point of playing, afterall. The Gophers are 1-0.
I have no doubt that MG will get "worked into the system" this year. He will see more time than the average blue-chip Freshman. And that will be a story in itself when you consider he's been kept off the field for two seasons.