College football’s spread offenses are producing wide receivers and quarterbacks ready to play as NFL rookies — and lots of linemen who need more prep for prime time.

ESPN analyst Jon Gruden recently bemoaned how quarterbacks have been under siege. He said the passers are to blame for not directing protections properly or getting rid of the ball fast enough but that the baby-faced behemoths aren’t keeping pass-rushers at bay, either.

“You’re getting a lot young offensive linemen out of college these days that have never been in a three-point stance, have never been in a huddle. They don’t have a real good background in how to get (in) the stance and get out of a stance and pass protect let alone pick up stunts, blitzes, handle audibles,” Gruden said.

“It’s a whole new world. I think that’s why you see a lot of teams running dive options with built-in bubble screens.”

Add in the fewer padded practices, the pendulum swinging away from TD celebrations and toward sack dances and QBs end up with bruised bodies the color of last week’s blood moon.

Pro Bowl guard Evan Mathis, who left behind an O-line in Philadelphia that’s struggling without him for one in Denver that’s struggling with him, gave an impassioned defense of rookie linemen, saying “some guys can learn that stuff in no time.”

Ravens coach John Harbaugh, however, said Gruden has “a valid point. It’s definitely something that we have to contend with all across the league.”

O-linemen used to the spread offenses are getting crash courses in the pros, learning how to disguise run blocking and pass protections. They are learning both technique and technical nuances while devouring playbooks and adjusting to quicker, stronger, savvier defenders.

“I don’t know whether the cupboard is bare, they’re all playing defense or what. It just seems like you get talented players, but you end up not having as many around that really know what they’re doing,” Denver offensive coordinator Rick Dennison said.

“And I’m not faulting anybody. They’ve got to do what they think they’ve got to do best to win, right?

“Offensive linemen, they’re always in a two-point, rarely are they in a three-point. Centers, oftentimes all they do is shotgun snap. We have to put them under center. But that’s just what it is. If that’s what the trend is, that’s what the trend is and we’ve got to just coach and teach more when they get here.”

Broncos defensive lineman Antonio Smith said that regardless of whether they come out of schools that run pro style or spread offenses, “usually rookie offensive linemen are easy to beat.”

“If you can tell that an offensive lineman is in a run stance or a pass because he’s not savvy enough to know how to disguise it, you’ve got the edge on him,” Smith said.

Zack Martin, the first rookie All-Pro for Dallas since running back Calvin Hill in 1969, played in the spread offense at Notre Dame but said his biggest adjustment wasn’t the style of play but the competition.

“It’s a very tough transition,” Martin said. “In college, you may go against one good guy and then for a couple of weeks have, not an off game, not an off day, but someone who’s not quite as good. In the pros, it’s every single week, every single day.”

Vikings second-year center Zac Kerin had to adapt not only to the higher level of competition and playbook complexity but also the simple proximity of his quarterback.

“One of the biggest things at Toledo was we were hardly ever under center,” he said.

Titans O-line coach Bob Bostad said the good thing is that the players who make it this far have what it takes.

“Obviously, they did very well wherever they were at or otherwise they wouldn’t be here. They did whatever was told of them very, very well by their coaches,” Bostad said.

“The thing that I notice different is if you do see a guy that comes from a particular school and they didn’t run that particular scheme then they’re a little bit behind. … That’s where they’re playing catch-up. But you’re going to be playing catch-up anyway — you’re learning somebody else’s scheme.

“We’ve got a guy here from a spread offense and I’m pretty impressed with him.”

That would be rookie right tackle Jeremiah Poutasi, a third-round pick from Utah who went from a power, three-point stance as a freshman to a two-point stance his sophomore year.

“As soon as I got here, I put my hand back on the ground,” Poutasi said. “I feel a lot more comfortable firing off the ball. I feel like me firing off the ball in a three-point stance is way better than firing off the ball in a two-point stance.”