I think I've just been real bad at trying to be a football expert for the past year. I'll be honest, I haven't really thought all that much about the secondary. I don't know why, so don't ask, but I just haven't thought about it enough.
I dont' know why this didn't click with me before, but I've always just somewhat assumed that the strong safety and free safety were your traditional safeties and played to the strong side and weakside of the field for the defense.
This is not accurate and I hope that I can help you sound like a football expert by the time we're done, at least a football expert for the secondary and specifically for Texas Tech.
Texas Tech's secondary plays the entire secondary, not just the cornerbacks, field and boundary. That includes the safeties. Essentially, the strong safety is the field safety and the free safety is the boundary safety. We should just start using these terms between each other in the future so that we all look like football geniuses. Again:
Field Safety (wide side of the field) = Strong Safety
Boundary Safety (short side of the field) = Free Safety
Like I said before, I'm sure that this is going to make me sound like a football dummy, but I'd rather admit my failings than ignore it.
With this new knowledge, I now understand that what this typically means is that most teams that play the secondary to the field or to the boundary determine the strength of the field based upon placement of the ball and most teams that align their defense this way play Cover 6 coverage. As an aside, the NFL team that run this (apparently) is the Pittsburgh Steelers.
A Cover 6 is nothing more than a combination of a Cover 4 and a Cover 2 (4 + 2 = 6). Sometimes, it is also called a quarter-quarter-half. Also, when you run two different types of coverages in the secondary it is called "Split Coverages". The corner and safety on the field side (which I think the Texas Tech coaches call the strong side) will run quarters covers, or a Cover 4, and the corner and safety to the boundary will run a Cover 2. The best photo or graphic that I've found is from a site called Code And Football and it helps me visually understand how it works. The graphic that you are looking for is called QQH Coverage and should be the 8th one down.
To break it down, the strong side or field side is Cover 4, while the weak side or boundary side is Cover 2.
Cover 4 and Cover 2 are pretty simple concepts. The Cover 4 means that the cornerback and the safety split half the field, while with the Cover 2 means that the safety needs to cover half of the field all by himself. More than anything else, I would hope that this helps you adjust your idea as to how you might think about each position and what they need to do. For example, Troy Polamalu is the Field Safety (i.e. strong safety) which means that he's playing a Cover 4 and so you get the idea that with the right sort of safety, maybe Josh Keys, a guy that can really come up and support the run and be really impactful, then this could be a real benefit for the defense. And the reason why this is a spot where Polamalu can have so much success is because the Field Safety can have a linebacker fall back into coverage just as easy as he can step up and blitz or attack the run once he makes that recognition.
To help me gain a better understanding of how this all works, I found articles from FishDuck, Big Cat Country and Wikipedia. The advantages and disadvantages mentioned in the Wikipedia article are just about spot-on for the weaknesses of the secondary and it makes sense to me after figuring all of this out. And the FishDuck post is really fantastic to explain why teams should or shouldn't run split coverages:
Yeah, I think split coverages are great, but they do have weaknesses. Motions and shifts (like Wisconsin and Stanford like to use), can cause a lot of checks in quick succession. Sometimes it may be smart to check to a more vanilla coverage upon a motion or a shift. This is what TCU has done when a receiver goes across the formation.
Another drawback, especially for quarters based coverages, is deep crossing patterns and play-action routes that settle in that 8-10 yard range which can cause poor matchups on the outside. It may get a safety to settle his feet and hips and sit on the #2 receiver when the #1 receiver is running an inside breaking route like a post. This can be a big play problem.
In addition, intermediate crossing patterns (8-15 yards deep) that have players on the backside working to the front-side may allow offensive players to find a nice hole in the zone if the #1 and #2 receivers to the strong-side clear out the safety and corner to that side because they get locked onto their receivers.
This makes sense and I could envision when teams do go in motion, then they'll just check out of the split coverage and run a Cover 2 or a Cover 4, not that big of a deal, but still, a real interesting concept that I had not considered.
One other thing, which is that Texas Tech may not really run split coverages, which is fine, but at the very least, this gives you a pretty good idea as to how Texas Tech really lines up (based on the placement of the ball) which I frankly didn’t "get" until the weekend. And from what I can tell, right now, the Field Safeties are J.J. Gaines, Josh Keys and Jalen Barnes, while the Boundary Safeties are Keenon Ward and Dorian Crawford.