"Your No. 1 pick is not what it used to be," Arians said. "Tony Boselli ain't coming out now – because he's a in a different offense – to plug in at left tackle right away. Or anybody else. There's so much more teaching involved with these younger players now. Much greater athletes, but much more teaching on our part."
Arians doesn't begrudge college coaches for failing to prepare their players for the NFL.
"Their job is to win games," Arians said. "I'd be doing the same damn thing if I was coaching in college with the 20-hour rule. I'd get the best athlete I could, put him back there (at quarterback) and spread it out."
http://www.azcardinals.com/news-and-events/article-2/Patience-Needed-More-Than-Ever-With-Rookies/5187055c-5bd0-48d1-9673-3ab5d7a3ff9b
He's made similar comments like this in the past, discussing in particular how few OL are ready to transition to the NFL game these days.
"You're drafting a guy right now coming out of some colleges that haven't been in a three-point stance since high school, and you're going to pay him a ton of money. You have to teach him to get in a three-point stance and run block," Arizona Cardinals head coach Bruce Arians said. "It's fundamentals that we're going back now and have to teach. We never had to teach it before. Great athletes. The athletes are much, much better, but the fundamentals are worse than they've ever been."
While QB's get the bulk of the attention, I think OL coming out of these spread offenses where they are rarely asked to be in a three point stance, aren't taught proper fundamentals and have just as much of a learning curve to become consistent players. You also get guys that aren't used to handling a lot of different things and you have a hard time determining how fast they process what is happening out on the field, much like the QB's, Mark Schlereth touched on that.
We run 40s. We jump over boxes. We do verticals and broad jumps and all that baloney that we do at the combine. And, we can get an elite level measurement of athleticism. But there's also elite level reaction time, and processing ability.
What I have found is that guys who can process information at the elite level and make a decision and then go hell-bound for life and go try to knock somebody out, those are the guys who can play at the next level. When you see guys with elite level athleticism and they get drafted high in the first round but they look like they're playing in slow motion on the football field, those guys to me don't have elite-level processing ability. When they see something, their body delays. So they may be able to run a really fast 40 or jump really high, but their reaction time is slow, because they don't process at an elite level.
You see it with quarterbacks. That's another position – guys that can process information instantly and make a decision and get rid of the ball, or guys holding onto the ball and not knowing where to go with it and the whole system just falls apart. The guys that process quickly, in my mind, that's a far better determining factor.
http://milehighsports.com/exclusive-in-the-trenches-with-former-broncos-ol-mark-schlereth/
The problem you get into with young football players, especially young offensive linemen, is the college game does a very poor job of grooming them to become professionals. It's a different game. And so, for the most part, there's a huge learning curve from the standpoint of they don't know how to strike people, they don't know how to use their hands, they don't understand leverage. They just really don't understand the game. It's just such a different game. There's a huge learning curve.
Jon Gruden chimes in as well.
In a recent conference call, ESPN analyst and former NFL head coach Jon Gruden expressed similar concerns.
"You're getting a lot of young offensive linemen out of college these days that have never been in a three‑point stance, have never been in a huddle," Gruden said. "They don't have a real good background in how to get the stance and get out of a stance and pass protect, let alone pick up stunts, blitzes, handle audibles. It's a whole new world. I think late in the season, no one's wearing pads on the practice field. They don't pad up on the practice field in training camp nearly like they used to. There are a lot of linemen changing teams more so than I've ever seen before ... I think that's why you see a lot of teams running dive options with built‑in bubble screens."
http://www.si.com/nfl/2015/09/09/mythbusters-declining-offensive-lines-spread-offense