That is a very good question.
Do some research and you could answer your own silly questions. He was injured with a pulled leg muscle. Simple fucking math: Hass was out, he is the #1 QB. Wallace was out, he is the #2 QB. That leaves Frye, #3 QB. Pretty fucking simple, no?
That being said, anyone who is dumb enough to put any money on Seattle on the road should have their head examined.