When his quarterback takes off running, Tennessee Titans coach Ken Whisenhunt only worries if he picked up the first down and what play to call next. Kansas City coach Andy Reid wants the quarterback on the ground as soon as possible. Seahawks coach Pete Carroll doesn't want Russell Wilson hit but sees his quarterback running away from defenders when not in the pocket.

How the quarterback finishes off the run — sliding feet first or diving forward with the head — is only an issue when he gets hurt.

"It's just like telling your children to be smart when they drive their car," Whisenhunt said. "It's an important part of it, but once they're out there on the field, it's in their hands."

Being healthy enough to take the next snap is a crucial part of the job for an NFL quarterback. Yet even with all the mobile quarterbacks now in the league, the simple act of sliding feet first to be protected by rule from defenders seems to be a lost art.

Cam Newton, who has the most yards (2,032) and touchdowns (28) running the past three years of any quarterback, missed the Carolina Panthers' season opener after cracking his ribs going headfirst at the end of a run in a preseason game. Playing with a flak jacket Sunday, he took off twice. Geno Smith of the New York Jets went headfirst in the opener a couple times and slid once against the Packers in Week 2.

Tennessee's Jake Locker missed the final seven games of 2013 hurting his right foot on an option play where he dove forward for more yards. The Los Angeles Angels drafted Locker twice as a center fielder. So how did he slide on a baseball field?

"I was headfirst most of the time," Locker said.

Wilson, who played in the Rockies' system as a second baseman, took part in the Texas Rangers' spring-training camp a few weeks after winning the Super Bowl earlier this year. Colin Kaepernick of San Francisco threw two no-hitters in high school before choosing football. He went headfirst with several Bears approaching Sunday night, a play wiped out by a hold. Bears quarterback Jay Cutler finished off a 25-yard run sliding with his left leg out front.

Kaepernick said last week that finishing off a run is pretty instinctual.

"I mean I've been running the football since I was 8 years old, so I'm not too worried about it at this point," Kaepernick said.

Teams rarely have their quarterbacks practice sliding. After Smith's headfirst approach in the opener, Jets coach Rex Ryan said maybe Derek Jeter could teach Smith to slide. Panthers coach Ron Rivera joked last month he might need someone from the Triple-A baseball Charlotte Knights to teach his quarterback how to slide. Rivera wants Newton to slide but doesn't want to take away who his quarterback is as a player.

"He can't help himself (and) he ran a couple of times. He did the best he could with it," Rivera said of Newton.

Reid would rather his quarterbacks slide feet first, but he also recalled having a pretty good one who went headfirst. That would be Michael Vick in Philadelphia, who missed three games in 2010 after getting hurt leading with his head but returned for a career year. He still slides headfirst.

Whisenhunt said the Steelers tried getting Kordell Stewart to practice sliding.

"He was awful, and it just wasn't worth the time," Whisenhunt said. "Then he ended up doing OK in the games. I think it's more about understanding where you are on the field and what's around you. But at some point, and I think I've said this, it's fourth-and-1, it's a goal-line play, you got to play football."

Peyton Manning, the five-time NFL MVP with the surgically-repaired neck, took off in a preseason game with San Francisco. Facing second-and-8 at the San Francisco 9, Manning made an ill-advised run and got a yard before being smothered by linebacker Aldon Smith. Both Manning and Denver coaches were evasive about whether that was a designed draw for someone who had zero yards rushing in 2013.

"It's a tendency breaker," Manning said. "You try to catch them off guard. It's probably not really high on their alert game plan sheet, 'Watch for the quarterback run.' I thought I was going to score, but I got 1 yard. Kind of humbling."

Anytime a quarterback runs, defenders can land a lick that won't draw a flag as long as he goes headfirst. The biggest challenge for defenders is looking to see if the quarterback is sliding or diving. Going headfirst means hit away, as long as they avoid the quarterback's head.

"You want to remind that quarterback to stay in the pocket," Titans safety Bernard Pollard said.

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AP Pro Football Writers Arnie Stapleton and Rob Maaddi and AP Sports Writers Tim Booth, Janie McCauley and Steve Reed contributed to this report.

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Follow Teresa M. Walker at www.twitter.com/teresamwalker