Safety is in the pocket.
That's what NFL coaches historically have believed about their quarterbacks.
Tell that to Tom Brady, Peyton Manning and Philip Rivers, all relatively stationary passers who have had major surgery during their careers.
Then again, having a quarterback double as a running threat doesn't thrill most coaches, either - even when it's Michael Vick, Russell Wilson or Robert Griffin III scooting around.
"You want your quarterback to be at his most effective," Redskins coach Mike Shanahan says. "You also want him healthy and in the lineup."
Which presents a predicament for Shanahan and his peers: QBs such as RG3, Wilson and Cam Newton can't be expected to flourish if they're restrained.
"You don't rein in a thoroughbred," says former Jets and Chiefs coach Herm Edwards, now an ESPN analyst. "They bring the ability to make a play that you didn't draw up."
On the other hand, few QBs who stray from their blockers have been champions. Not even John Elway, Brett Favre and Ben Roethlisberger, quarterbacks known for making big plays on the move, could be classified as runners or scramblers.
Still, don't underestimate how much of Aaron Rodgers' skill set is built around his mobility with the Packers.
"He does a good job in the pocket transitioning out of the pocket," Green Bay coach Mike McCarthy said. "I mean the quarterback scramble drill is something that we believe in. We practice it from Day 1. The in-pocket training for the quarterback is detailed. The out-of-the-pocket training for the quarterback is detailed.
"The true art of it - and it's a great credit to Aaron - is the transition from the in-the-pocket training to out-of-pocket training. ... It's something that's part of our passing game, it's something that's coached, and he's exceptional at it."
A changing game
Every Super Bowl since 1996 has been won by QBs who prefer being in the pocket, although Brett Favre, Elway and Rodgers surely weren't fearful of taking off. Brady, Peyton and Eli Manning, Roethlisberger, Drew Brees and Troy Aikman are in that group of pocket passers.
But of the 12 teams in last season's playoffs, half had quarterbacks who used their legs to complement their arms: Rodgers, Colin Kaepernick, Griffin, Wilson, Andrew Luck and Christian Ponder. Atlanta's Matt Ryan and Joe Flacco aren't statues, either.
Coaches no longer cringe when passers are forced out of the pocket. Well, most coaches: John Fox doesn't want to see Peyton Manning running any more than Tom Coughlin enjoys watching Eli do it.
Generally, though, coaches, coordinators - and teammates - are learning to swallow hard and encourage their athletic QBs to make plays, provided the quarterbacks have escapability. Yes, there is the vulnerability issue, as everyone saw when Griffin tore up his knee in the playoffs. But, again, holding them back can lead to uncertainty, frustration, or a loss of confidence.
"I think ... you watch him run and you advise him, give him tips. Certainly, the whole team is coached on how to run, protect the football," 49ers offensive coordinator Greg Roman says of Kaepernick, who set a postseason record for yards rushing by a quarterback last winter with 181 against Green Bay.
Roman, a native of Ventnor, N.J., who coached Holy Spirit High School, adds, "But he's a very naturally gifted runner and I think he's got good instincts on when to hold them and when to fold them."
Kaepernick's new target with the Niners, Anquan Boldin, doesn't think the quarterback should fold them.
"From the outside looking in, you hear about how athletic he is," says Boldin, who was on the other side when Baltimore beat San Francisco in the Super Bowl. "A lot of times, the quarterback aspect gets overlooked. I think if people have a chance to play with him or see him up close, they'll understand how good of a quarterback he actually is.
"With Colin, the play is never dead. You just have to keep that in the back of your head. Even if the defense has a great call on you or it looks like the play is broken down, he has a knack of getting outside the pocket and being able to find receivers."
That's a trait many quarterbacks might have owned from the outset, but outside of a Steve Young, Vick or Randall Cunningham, few were encouraged to use in the pros.
Rolling to success
Rodgers gives the Packers the best of all worlds, something RG3, Kaepernick and Wilson might provide at the same level if they maintain their early progress and success. Rodgers is dangerous inside the blocking shell and even more of a threat on the move; his passes, when rolling out, are more accurate and stronger than many other QBs, even some Pro Bowlers.
"Your mentality when you're blocking for him is make sure you stay engaged. You can't have a time clock in your head, thinking the ball might be gone," guard T.J. Lang said. "You've got to stay locked up with those guys, match their effort. ... Whenever we do that, we give Aaron some time, he tends to make a lot of big plays."
Big plays are what quarterbacks are all about these days as the NFL has skewed toward lighting up scoreboards with the passing game. Brady, the Mannings and Brees, pocket passers all, remain as prolific as ever, operating from the pocket.
But they might be an endangered species. Nearly every highly drafted quarterback in recent years has been of the Newton-Griffin-Manuel mold, with mobility an inherent part of their makeup. Even Luck, a trained pocket guy, has terrific mobility.
"Coaches are well aware, especially at quarterback, that it's not the system but the player who comes first," says Edwards, who has studied closely the shifting philosophy at the position. "Now more coaches are subject to building the system around the player you have, and the colleges are producing this type of quarterback.
"And they can play. They are ready. So you let them play."