Just read an FBG article by a guy who was watching the film of the game and has watched Lance before that Lance takes some solid hits because he doesn't slide very quickly and just runs through guys. I saw it in his highlights from North Dakota St. where I was like "get down, man!" So I don't think the film watcher is far off.
What's my point? You may see Jimmy G by the fifth game, but not for benching reasons.
Also, my other point: Lance is going to be fine. Everything I've heard reported and everything I've seen is that he's a better QB than Jimmy G. The color commentators in the booth wince whenever Jimmy G plays. He's just not very good, Super Bowl appearance or not. (And since when did that mean anything? We can all agree Trent Dilfer was a pretty terrible QB, right?)