I had heard something on this thread on removing the injury guarantee. As best I can tell, that still hasn't happened.
Keap is likely Chip's ideal QB, but SF @ BUF might be the single worst time to try it. With the Eagles he had Bradford on a rebound. Right now, the Niners have even worse receivers than Philly, and the 31st run defense. Even if Chip can dial up some plays we should be able to grind it in the first half.