Directly from IGN...
IGN was advised by a Marvel spokesman today that the rumors are entirely untrue, that Johnston remains aboard to direct and principal photography has not been delayed. Of course, short of a press release declaring otherwise, that's exactly what the studio would be expected to say. We were also advised that no one has been cast as Cap yet and thus no deals have been made.
So this should also put the John Krasinski rumor on hold...for now. But I'd like to point that the list of actors to screen-test for the role, was in fact only a "Wish List", not folks in the running. So there you have it. I know this should makes some folks happy...for now.