Here's the link to Parcells' press conference in which he describes how we played quarters coverage. This was one week after the Moss touchdowns, and he was talking about an 89-yard TD pass to Brandon Lloyd in our game against the 49ers.
Link:
http://play.rbn.com/?url=nfl/nfl/open/cowboys/demand/parcells_092605.rm
Starting at 11:30 of the press conference --
Reporter: It seemed like you were talking to Davis on that long play to Lloyd. You know, y'all had an extended discussion over there.
Parcells: Yeah, I sure did.
Reporter: Did he do something wrong on that play? Because it looked like he didn't think he did.
Parcells: Well, I know, he didn't think he did, but he found out different.
Reporter: What did he do wrong?
Parcells: Well, if you really want the actual explanation, we were in a quarters coverage, OK, and uh, there was no vertical threat on his side. It was a play-action pass away from him, so he basically was free of any responsibility. Well, the only responsibility, the only receiver left on his side was the guy that caught the ball. So why wouldn't you turn, with no other threat, wouldn't you turn that way to help? That's what you should do, and he didn't do it. So he's just back in there doing nothing. OK?
Reporter: Taking up space.
Parcells: Well, he's taking up his space, OK, when he should be realizing that he wasn't threatened. OK, now, 'where can I help?' You're certainly not going to help the other corner. He's way over there, two positions over. So. that's part of those growing pains I'm telling you about. That's part of the growing pain, right there. Not enough experience.
Reporter: Isn't that what he did, though? Didn't he peek inside on the slot receiver?
Parcells: Well, yeah, he might have, but a tenth of a second after the ball was snapped, he should have looked for the X (receiver). A tenth of a second. Because both backs ... had no vertical threat. It was just a split end on his side. They were in I formation. Simple.
Now, does anyone want to claim that we weren't playing quarters coverage on Lloyd's touchdown catch? Anyone? Anyone?
OK, then. Let's take a look at the play, a second-and-19 from the 49ers' 11 with 7:56 left in the second quarter.
Here's the pre-snap look at the offense and defense ---v
In the photo above, you can see that we're in a 3-4 defense. Ware is on the defense's right edge, ready to rush against the left tackle. Al Singleton is out to the defense's left to bump the slot receiver. The two inside linebackers are about 4 yards off the line. Newman is at the bottom left against the Y receiver. Henry is at the top right on the X receiver, Lloyd. Roy Williams is the safety on the left, and Davis is the safety on the right.
In quarters coverage, Newman and Henry will play man-to-man on the outside receivers. The three linebackers in coverage will play zones underneath. Roy will key on the inside receiver on his side (the slot receiver in this case), and Davis will key on the inside receiver on his side (the running back). If the inside receiver runs a vertical route, the safety plays man-to-man on that receiver. If not, as Parcells explained, he doubles the outside receiver.
Here's what it looked like immediately after the snap ---v
In the photo above, you can see the play-action fake that Parcells was talking about. The running back is not coming out of the backfield to run a vertical route. That immediately shifts Davis from his primary responsibility (the inside receiver running a vertical route) to his secondary responsibility (doubling the outside receiver). Parcells says Davis should know this "a tenth of a second" after the snap, but Davis doesn't do that, as you'll see from the next two photos.
Still looking at the photo above, you can see Singleton bumping the slot receiver and Newman, Henry and Roy in position to cover their respective primary responsibilities.
Here's the next photo ---v
In the photo above, you can see Singleton releasing the slot receiver to Roy and the three linebackers staying in the short zones. Newman and Henry are playing man-to-man. Roy is about to break on the slot receiver. Davis is -- as Parcells put it -- taking up his space, rather than doubling the outside receiver.
The next photo ---v
In the photo above, you can see the three linebackers still playing the short zones, Newman and Henry playing man-to-man, Roy breaking on the slot receiver's post route and Davis still taking up his space, looking into the backfield as Lloyd races past him.
The next photo, just after the ball is thrown ---v
Again, in the photo above, you can see the three linebackers playing the short zones, Newman and Henry man-to-man outside, Roy covering the post from his inside receiver and Davis just now breaking back toward Lloyd.
And the catch ---v
Davis is already 5 yards behind Lloyd because he didn't double him immediately after he realized he had no vertical threat from the inside receiver.
Are there any questions NOW about quarters coverage and EXACTLY what the safety's responsibility is in that coverage?
Can you do the same thing for the Washington game in question? I'd like to see where the actual misplay was. Purely for educational reasons. 
