It's funny/odd how DC's have a tendency with coverage against rookie QB's. I've noticed the majority of the time rookie QB's will face man-to-man coverage (press) in their first few weeks, until they show they can consistently beat man-to-man coverage.
This means that when QBs to WRs are insync, defenses will tend to fall back on zone coverage, often with a safety deep, but with rookie QBs, DC's have a tendency to play man-to-man coverages a bit longer, sometimes the entire game.
DC's will also often blitz on the the QB's strong side (from his right if he's right handed, left if he's left handed), then do blind side blitz too keep up the pressure level and induce panic and poor decisions from QB.
So how is this helpful? Well with rookie QB's, if you've watched them in college and nfl preseason, you get a sense if they can beat man-to-man coverage. This will allow you to take a chance on rookie QB's.
Over the first few weeks DC's will often disguise their coverage, often showing man and switching to zone, and this is where QB's create separation from each other. The great QBs aren't fooled often by disguised coverages. The average QBs are fooled half of the time and the rookies are fooled often.
In short, DC's tend to follow this path...
* Beat man-to-man (QB to WR synchronicity [is that a word? lol])
* Beat man-to-man with blitzing [tests OL and RB/FB blocking as well as, how soon will QB a) choose to run with ball? or b) choose to throw ball away? or c) find hot read? ]
* Beat 7 in the box (will QB change play from pass to run? Is he allowed to do so? [more so @college level than pro's)
* Beat single safety deep (show me big arm accuracy)
* Beat two safety deep (force the QB to have long drives, dink and dunk)
Of course in the red zone, QB accuracy is a premium as well as timing with WR's, and IMO play calling as well. So what's a DC do? He'll likely do the same as above, with more emphasis on stopping run plays first.
It's a win for a DC for every drive that ends without a TD, half a win without a FG, hopefully the DC will get recognition for his playcalling, but it's the O that gets most of the glory as well as most of the blame.
Another noticeable trend is the cyclic nature of QB/Team performance, when an offense tends to perform well, it'll last 4 to 5 weeks at a decent to high level. Then noticeably taper off as DC's have had time to study and adjust. The good QB's change, the average struggle, the bad have not many options. You may often notice OC's going to more runs plays after that first loss, but struggling if they get to far behind with their pass play choices. Keeping a D off balance is both art and a mystery to me w/QB's and OC's insync for a few teams. The rest have yet to find that happy ground or 50-50 balance of pass to run ratio, but sometimes IMO it's not as necessary as play calling is the real key with player execution.