Playing offensive lineman is a job like no other in the NFL.
The standard job description: Weigh at least 300 pounds, be strong and aggressive enough to push around a man just as heavy against his will, expect to toil in anonymity unless a mistake is made.
A thick skin also is a must — no player holds an offensive lineman to a higher standard than the man who lines up beside him because the unit is literally only as strong as its weakest link.
"With offensive linemen, there's a hierarchy," said Brad Hopkins, whose 188 games at left tackle with the Tennessee Titans was more than any other left tackle in the NFL between 1993 and 2005. "There's a hierarchy of experience, there's a hierarchy of toughness, there's a hierarchy of expectations, and every offensive lineman in that unit has to fall in line.
"They'll jeer, they'll tease, they'll poke, they'll prod and depending on how much you take, that's where you are in that rung of offensive linemen."
A report on the Miami Dolphins' racially charged bullying scandal detailed how the locker-room culture apparently went too far, with several offensive linemen at the center of the harassment case, including Richie Incognito, Jonathan Martin and their offensive line coach.
Their alleged behavior of vicious taunts and racist insults was even unacceptable by NFL locker rooms standards.
Still, NFL linemen believe each man in the unit has to be accountable because they hit, and get hit, more than any other player.
"The other guys in that unit are saying, 'Hey look, we need you to step up. Not just to defend yourself, but defend us if we need be,'" Hopkins said. "We are a unit. We play as a group, OK? Which means if I'm over here getting my head caved in, I expect you to come over 100 mph and peel that guy off.
"I can't be questioning your heart."
And there can be no question about a player's toughness.
Offensive linemen pave the way for running backs and protect star quarterbacks — and take pride in dominating opponents. But they can be an aloof group, sticking mostly to themselves because they feel no one else on the team can identify with their jobs.
In Carolina, the O-line has always been a clique unto itself.
Panthers Pro Bowl tackle Jordan Gross once rented a full-size Winnebago for training camp in Spartanburg, S.C., where players could relax and play cards during breaks from practice and meetings — a little air-conditioned paradise away from the intense summer heat.
The lone rule: Only offensive linemen allowed.