By Andy Staples, SI.com

The most important assistant coach in America won't watch the field Saturday. He'll watch the sidelines.

Meet Coach Getback, the man whose role grew much more important this offseason thanks to a new NCAA rule change. What position does Getback coach? None. His job on Saturday is to stand on the sideline and yell "Get back!" should any player or coach dare try to leave the rectangle between the 35-yard lines without permission.

This offseason, the NCAA eliminated sideline warnings and ordered officials to flag teams immediately should a player or coach venture out of "the box." That could lead to some surprise penalties if Getback doesn't do his job. The first two sideline infractions will draw 5-yard delay-of-game penalties. All subsequent infractions will draw 15-yard penalties.

Marshall's Coach Getback, Mike Cochran -- whose day job is head strength coach -- learned how critical he had become last week when Conference USA officials visited practice to show the Thundering Herd how the new clock and sideline rules will work in a game situation. An official invited Cochran to walk the sideline with him, pointing out every player or coach over the line. "He said, 'There's 40 yards of penalties right there, coach,' " Cochran said.

At most schools, the title of Getback is bequeathed to the head strength coach. This makes sense, considering he might be the only one on staff strong enough to keep a hormonally charged, 300-pound defensive tackle from stepping over the buffer line a yard away from the sideline to celebrate a 20-yard pass by his team's offense. This season, if the side judge or line judge is paying attention, that happy defensive tackle could kill a drive.

"It's going to be an issue somewhere," Cochran said. "It could really affect somebody's game."

Of course, the players usually aren't the worst trespassers. Getback has to worry most about the millionaire in the headset. "I don't think we've had a problem with that. If it is, it's just me," Florida coach Urban Meyer said. "They usually shout, and I get back." Cochran, who uses two grad assistants to help patrol the sidelines at Marshall, said one will keep an eye trained on Herd head coach Mark Snyder.

And in the heat of the moment, Getback can't afford to be cordial -- even if that means screaming at his boss to avoid a penalty. That, Cochran said, is the most important thing Coach Getback must remember. When you guard the sideline, you have no friends. "You've got to be as big a [jerk] as you possibly can," Cochran said.