Throwing deep to Harvin probably cost Geno his job. Took all of 11 minutes.
Watch Harvin on that deep route; he can't locate the ball, doesn't break up the INT, and loses all balance while trying to turn around. I've seen him look similarly lost on throws that appeared to "miss" him in Seattle. He'll probably break one out at some point, but throwing deep to him just isn't a high percentage play. It's amazing that people think it's some coincidence that no one at the college or pro level thought to use him as an outside receiver. There's a reason for it.
Just running fast doesn't make you a deep threat at this level. You need ball skills. Need to be able to get off a jam. Need to able to run through the route tree. Harvin just doesn't excel in those areas. He's a dangerous player in several respects, but the fact is that you need to run a gadget-heavy offense to get him involved.