So San Francisco Giants ace Madison Bumgarner has dipped since the fifth grade? The NFL has its tobacco stories, too.

One quarterback in an NFL training camp is so self-conscious about his dipping, knowing his mother wouldn't approve, that he places a gold grill over his lower teeth to hide the nasty brown habit.

Former Bears quarterback Jim McMahon's smokeless tobacco use was no secret in 1984, but the NFL no longer allows players to chew during TV interviews or on the playing field. AP Photo/Charles Knoblock

While Major League Baseball has spent years trying to curb chewing tobacco use in its game, the habit has permeated locker rooms for decades in the NFL, which does little to address the topic despite smokeless tobacco's links to oral cancer and nicotine addiction.

Anywhere from 75 to 80 percent of the players in the Browns' locker room chew tobacco or used to do so, former Cleveland punter Spencer Lanning, now with the Denver Broncos, estimates. Two Steelers players say usage in their locker room falls between 65 and 75 percent.

"Some started in college, others didn't do it until they got to the pro level, but it's widespread," Lanning said. "I've never been on a team that didn't have at least half or 75 percent that did it."

Those percentages double the range gleaned in a 2014 Boston Globe report citing 21 of 58 Red Sox players at spring training (36.2 percent) admitting to dipping.

After two decades coaching in college and the NFL, Steelers quarterbacks coach Randy Fichtner has struggled to kick the habit. He hasn't suffered any health issues yet but knows he could.

Former Browns punter Spencer Lanning says around three-quarters of the team's players used chewing tobacco. Ken Blaze/USA TODAY Sports

"I've rode that roller coaster before, and I'm probably not very nice to be around when I [try to quit]," Fichtner said. "It's not anything I'm proud of. ... It's a habit. I'm going to get up, I'm going to take a shower, go to a meeting, first thing you do [is throw in a dip]."

Approach to tobacco: MLB vs. NFL

With baseball, tobacco is full frontal. Fans can see the players using during games. The death of Tony Gwynn, a longtime dipper who suffered from salivary gland cancer, has raised awareness about the long-term effects. Smokeless tobacco users absorb more nicotine than cigarette smokers, according to several medical websites, which also cite dehydration, gum disease, tooth decay and links to cardiovascular diseases as risks.

MLB feels that pressure. Smokeless tobacco use has been prohibited in the minor leagues since 1993. The city of San Francisco passed a law in May banning smokeless tobacco in the city's sporting venues, including AT&T Park, Bumgarner's home field. Boston Mayor Marty Walsh recently proposed a similar ban for his city.

In football, though, tobacco is reserved mostly for meeting rooms and corners of locker rooms, a stimulant to aid concentration during a boring day of film work and walk-throughs, players say.

Madison Bumgarner can't dip during home games after San Francisco passed a law banning smokeless tobacco at the city's athletic venues. Lachlan Cunningham/Getty Images

While MLB in 2011 proposed a tobacco ban (players shot it down) and strongly discourages clubhouse attendants from purchasing tobacco for players, the NFL doesn't manage its use at team facilities.

"I don't think the NFL cares much because it's all done behind the scenes," said Phillip Daniels, a defensive end with the Seahawks, Bears and Redskins from 1996 to 2010. "It's not a PR issue."

Dipping has been a part of NFL culture since at least 1980, when former Houston Oilers running back Earl Campbell promoted Skoal in a commercial shot on a beach.

The NFL does have two rules when it comes to players using smokeless tobacco -- don't do it on the playing field or while conducting television interviews. The Bills found this out in November when CBS cameras caught Kyle Orton on the sideline sliding a wad of dip into his mouth during the latter stages of a 26-10 win over the Browns. The clip made the social media rounds for a few days, and the NFL had to address the matter with the Bills, who won't comment on whether the league levied a punishment as a result.

The NFL denied interview requests with league officials on player health as it relates to tobacco. Three teams were unresponsive to requests for team trainers. An NFL spokesman said players receive education about league policies relevant to them at the NFL's rookie symposium or at annual information sessions at training camp.

Chewing is part of the game, former Browns general manager Phil Savage said -- "from high-profile coaches down to low-level staffers."

The Bills won't say if the NFL penalized them after Kyle Orton was caught on camera last year putting a dip into his mouth on the sideline during a November game. AP Photo/Joe Mahoney

Former NFL general manager and recent Hall of Fame inductee Bill Polian doesn't go that far, because he has seen teams stop supplying tobacco to players over the past 15 years because of health concerns.

"It's around, but I wouldn't say it's as prevalent [as baseball]," Polian said.

Why and how it's used in the NFL

When walking through several NFL locker rooms in recent years, it's been noticeable that some of the game's elite athletes -- running backs with sub-4.4 speed, for example -- will chew before or after practice.

Skoal, Grizzly and Copenhagen are the primary brands used, and players trade them like kids with baseball cards.

Many current players with a dipping habit are aware of the stigma attached to it and as a result don't want to be interviewed on the record about tobacco. One NFC head team trainer scoffed at the idea, calling tobacco use in the NFL a "non-story."

But Daniels said he has been on teams with which trainers ask players for tobacco, and vice versa.

"Spit cups are everywhere," Daniels said. "It's gross. Guys know they have to quit eventually or they'll have serious problems. I've never seen players being warned by a trainer to not use it because of the health risks."

Retired defensive end Phillip Daniels says he didn't see team trainers discouraging smokeless tobacco use during his 14-season career. AP Photo/Nick Wass

Tobacco can help break up a monotonous NFL day. Players have meetings leading up to a walk-through -- which is really a "glorified meeting," Lanning says -- followed by post-practice meetings to break down what just happened on the field. About four to five hours on Wednesday or Thursday of a game week are spent sitting in a meeting room.

Steelers outside linebacker Jarvis Jones realized that routine was more challenging without the incentive of playing every week when a wrist injury sidelined him for nine games in 2014. Using tobacco pouches was "my way of coping" with the injury, Jones said. It helped keep him alert. Jones doesn't drink coffee, so this was a substitute.

"When I leave the facility, I don't use it," said Jones, who prefers "pouches, not the full-blown snuff."

"A lot of [players] use it."

Tobacco use isn't a way for players to bond, Lanning said, but "literally just something to do."

'They can't micromanage everything'

The risks aren't going away, which is why Fichtner monitors his son, who plays baseball at Memphis, where many players dip. His son does not. Fichtner would like to keep it that way.

Steelers quarterbacks coach Randy Fichtner, shown watching Ben Roethlisberger, has struggled to kick his tobacco habit. AP Photo/Keith Srakocic

If a player asks Fichtner to share tobacco, he says no. But he remembers the days when NFL teams kept tobacco in the refrigerator for players and coaches to grab.

"I wouldn't support it or tell these cats to do it because it's not healthy for them," Fichtner said. "But a lot of guys don't drink or drink coffee during the season, so maybe they feel this helps them, gives them a pick-me-up."

Players who don't know the risks are ignorant, Lanning said.

"You will have problems. They full-on accept that possibility," Lanning said. "[The NFL] doesn't talk to us about drinking alcohol. They can't micromanage everything. To me, alcohol kills way more people than tobacco."

But Daniels has known former teammates who had difficulty quitting after their careers ended, which worries him.

"With all the lawsuits that are out there, eventually maybe something like this could be an issue if a high-profile player has a problem," Daniels said.