Why so the suck against Indiana? A few things leapt out on the tape. One was YAC given up by a physical inability to be close enough to the receiver to tackle on the catch. This is the James Rogers problem, and it isn't going away. Another problem might: freshman defensive backs think "zone" means "man." BWS caught an instance of this and picture-paged Courtney Avery giving up a big gainer on third and sixteen because he dragged out of his zone.
That was an excellent example of cover three. Here Michigan will run cover two and get nailed on it. However, it's not Avery's aggressive coverage that's the problem here, it's the Michigan zone's obviousness and inflexibility.
The setup: Michigan is trying to keep Indiana out of the endzone on the final drive of the first half. IU's driven it just inside the Michigan 40 and has a second and ten. They come out in their bunch shotgun set. Michigan shows two high safeties:
At the snap four guys rush and Michigan is obviously in zone. They have JT Floyd and Mouton in the middle of the field, Courtney Avery playing in the slot, Terrence Talbott and James Rogers on the outside, and Kovacs and Gordon as deep safeties. Mouton drops into a zone to cover a potential slant and Floyd is sitting in the middle of the field about ten yards deep:
A split second later we see what's going on with this bunch at the bottom of the screen: two short routes breaking inside and out with one guy headed deeper. Rogers is essentially motionless as Avery starts moving with the interior WR: 
Avery follows… Rogers is motionless…
Avery follows… Rogers still not going anywhere… IU receiver still running to the sticks… Chappell throwing…
Alert: someone done failed.
Gordon comes over to clean up:
Indiana gets a first down inside the 20.
UPDATE: duh forgot the clip.
Who's at fault here? I don't know. I don't think anyone, really. Some guesses at object lessons:
- This, like Odoms sitting way down in the hole, is a pass that takes advantage of cover two. The sideline 15-20 yards downfield is always a weak spot. Not a lot of quarterbacks can exploit that as ruthlessly as Chappell can, though in this instance it's so open a lot of QBs could make the play.
- Michigan made this read easy by showing cover two and running it. Chappell knew it was zone because Michigan just about always plays zone and did not put another guy over the bunch, and as soon as Rogers sat down on the out he knew the corner was going to be open.
- Advanced zone defenses that use pattern reading can adapt to these routes better. I'm not sure about this, but the key is that someone has to be responsible for #2 going vertical and go with him. That would be either Avery or Rogers. The other would come up on the out, leaving the drag to Floyd. Michigan doesn't do this here and probably doesn't ever do it because they've got a secondary with three sophomores, two freshmen, and positional vagabond James Rogers. Also some defensive coaches think pattern reading is suboptimal for reasons I'm not 100% clear on yet.
- Avery seems like he's in great position if this was man coverage. He also broke up a slant against BG impressively. If Michigan ever ran man I bet he'd be pretty good at it. Can they do that? Eh… maybe against teams that don't spread the field. Here I think his coverage is good given the situation and the assumption Michigan is not pattern reading.
- But it's not man and the freshman corners do this all the time. There's the BWS post with an example, and Indiana's last touchdown was Terrence Talbott in great man coverage on a slant… when he had a zone to the short side of the field that held Darius Willis and no one else once he covered the slant.
- Can Gordon do anything more here? I don't think so, but I'm asking anyone with the knowledge. Is the safety's role here tackle and live to fight another day? What if this was Reggie Nelson?
There is some good news: Michigan did adapt to this route pattern, stoning it several times late. Indiana adjusted by sending the deep WR on a post and Floyd dropped back into it, forcing Chappell to chuck it high.