It's not weird now that I know a little more about the situation.
What we're looking at is basically two different offensive schemes. Not to the degree of a change in offense, but different blocking schemes with each QB.
They feel that Blake is better suited for an offense with a moving pocket. Coker, on the other hand, is one that excels in the same style of protection we've been playing. For lack of a better way to put this, we're looking at two different blocking schemes.
If we're going to use two quarterbacks in the first game I don't see a great way to do it. Play both, but make Blake stay within the pocket (while that doesn't suit his best attributes as a runner?) Play Blake, then switch to Jake, but play one style with a moving pocket then switch to a more traditional set?