The NFL has put safety measures into place amid rising concerns about players' risk of brain damage — but how much more can the league really do before it fundamentally changes the sport? Warren Little/Getty Images

Football fans like Jae Hill watch the game to see players perform feats of power, strength and passion, and they expect to see a hard-hitting show every time they tune in.

“Clearly I don't want to see anybody injured but at the same time, people are watching NFL games for the intensity,” says Hill, who has cheered for the Patriots since he was 16, but recently started rooting for the Seahawks upon moving to Seattle. “These men are paid millions of dollars to slug it out.”

In the aftermath of San Francisco 49ers linebacker Chris Borland’s abrupt retirement this week, American football is once again facing off against neuroscientists and health experts whose concerns about brain damage have dominated conversation around the sport. But at the same time, some fans, coaches and players see little room for the league to make America’s most popular sport safer without turning football into something else entirely.

Borland’s hasty exit rattled the NFL and its fans when he announced it in an interview on ESPN's "Outside the Lines" on Monday. The 24-year-old said he is concerned about the three concussions he sustained while playing in high school, college and during his one-season professional career. He told interviewers he fears the hits he took on the field may put him on the path to someday joining the over 70 league veterans now known to have been plagued by brain damage later in life following exams after their deaths.

Borland's decision was only the sport’s most recent setback in this regard. Since the 2013 "PBS Frontline" documentary "League of Denial" widely exposed the discovery of the neurocognitive disorder known as chronic traumatic encephalopathy (CTE) in the brains of former football players such as Mike Webster and Junior Seau, the National Football League has faced a growing chorus of critics who charge that the league has failed to be upfront about the risk of long-term brain damage that players may face from both concussions and sub-concussive hits. Critics also charge that the NFL has been slow to implement safety protocols that could lessen those threats.

An NFL investigation found that league veterans are up to 35 times more likely to suffer from Alzheimer’s disease and dementia than the average person and that one in three will develop neurocognitive problems.

In response to Borland’s announcement, the NFL proudly pointed out that the rate of concussions had dropped by 25 percent last season, and highlighted the steps it is taking to protect players. New protocols, for example, call for an athletic trainer to be stationed in the press box during games to offer a better vantage point to spot dangerous hits. The league also requires players who have a concussion to undergo a consultation with an independent doctor before returning to the field.

New concerns first raised by emerging evidence of brain damage and again by Borland's retirement have put the NFL in a difficult position. The league's executives know that scientific opinion on the dangers of the game is a force to be reckoned with – but so are football's loyal fans. The league must consider player safety while preserving the entertainment value that has helped the sport maintain its status as America’s most popular.

More than 17 million fans paid an average of $85 for a ticket and poured into stadiums around the country for last season’s games, while 202 million viewers tuned in from home. The NFL generated $9.2 billion last season in revenue from sponsorships, tickets, television rights and merchandise sales, up from $8 billion five years ago. And even the 2014 revenues are nowhere close to the $27 billion in revenue the league has said it expects to collect in 2027.

Jeff Miller, senior vice president of health and safety policy for the NFL, says the league will continue to review injury data that is tracked and charted by the biopharmaceutical company Quintiles and make changes that are in the best interests of the health and safety of its players. The league’s competition committee, which sets the official rules of the game, meets regularly with health and safety experts, he says, as well as players and coaches before voting on the sport's official policies.

“I don’t think there’s anything we won’t look at. We will go where the data leads us," says Miller. "If that data leads us to a conclusion about how changing part of the game can change player safety, we will take that very seriously.”

Some of the league's changes are already altering the way the game is played, and fans as well as former players are wondering if more dramatic shifts are in store. Fans often cheer loudly for brutal collisions -- almost as loudly as for touchdowns -- and a YouTube search for “NFL hardest hits” returns 70,800 videos, which is tens of thousands more than similar searchers for “best tackles” or “best kickoff returns.”

“It's a violent game, it's a physical game and it's been like that from the start. It's going to forever be that way,” says John Thornton, a former defensive tackle for the Tennessee Titans and the Cincinnati Bengals who played in the NFL for 10 years. “I don't know how you cut it out of the game completely. I think there’s always going to be someone who suffers a head injury." Thornton now works as director of client management for the sports agency Octagon.

In the past few years, the league has restricted the legal hits on quarterbacks and kickers, and limited the number of full-contact practices permitted during the season to only 14. The NFL also moved kickoffs from the 30-yard line to the 35-yard line, which has cut the number of concussions sustained on that play by 40 percent.

“That’s the single most violent play in football when people are running full-steam in one direction,” says Dr. Robert Cantu, a neurosurgeon at Boston University who serves as an adviser on the NFL's Head, Neck and Spine Committee and appeared in the Frontline documentary.

In February, the NFL also appointed Dr. Betsy Nabel, a cardiologist and president of Brigham and Women’s Hospital in Boston, as its first chief health and medical advisor to oversee the league’s policies on safety and player care, including proper concussion protocol, which is set by the Head, Neck and Spine Committee.

Cantu credits the NFL for all of these changes, which he says have helped cut back on concussions in the league. Still, he and other experts are calling for additional safety precautions that range from the procedural to the game-altering.

Though Cantu acknowledges that football is a hard-charging sport and will always be played that way, he says safety measures that tweak it ever so slightly can still strike a chord between ensuring player safety and meeting fans' expectations for the competitive game they love. Such a compromise may not sit so well with fans, players and coaches who have already protested the shift of kickoff to the 35-yard line in particular since it meant that far more kickoffs would lead to touchbacks instead of returns.

“Some of these new rules are diminishing the ability of these players to have those super exciting moments -- the big hits and the big runs,” Hill says. “It's absolutely exciting to watch that and those are the sorts of things that they are restricting.”

“Is that good for the game? I don’t think it is,” retired NFL special teams coach Mike Westhoff wrote in a post on Sports Illustrated’s website titled “The Touchback Era Is Ruining The Game.” “We’re in the entertainment business, and the league has taken away a lot of the entertaining plays.”

Game Changers

Despite those charges, health experts have no shortage of safety recommendations they would like to put into place. Dr. Cynthia Trowbridge, an athletic trainer and sports medicine researcher at the University of Texas at Arlington, says the NFL needs to ensure that its medical professionals -- who are tasked with taking concussed players out of games -- are supervised by other medics instead of coaches and general managers. This, Trowbridge says, would help to guarantee that a player's treatment is based solely on a healthcare professional's best judgment.

“They should be hired by a medical director who can assess their professional care,” she says.

Trowbridge adds that the league must support its players long after they finish their professional career. Right now, the health insurance that players receive through the NFL runs out just five years after a player steps off the field for the final time, reports the Washington Post. And players must complete three seasons to even become eligible for the brief coverage, which means that Borland is losing out.

“That's inexcusable given the money the NFL makes off these players because a lot of these problems don't start until long after five years,” Trowbridge says. Thornton also supports a longer insurance policy for players.

There are also other suggestions, some of which could fundamentally change the way the game is played, and are the sort that are more likely to drum up protest from players, coaches and fans. Cantu suggests ruling out all intentional hits with or on a player’s head, in line with findings that some forms of brain damage can occur from the thousands of day-to-day hits that players sustain which do not result in a concussion, as shown in a recent study led by researchers from Wake Forest Baptist Medical Center. Existing rules still allow linebackers to lower their heads to make a hit inside the tackle box.

“Will it be a totally safe sport? No, but back in the ‘50s, people weren't hitting people in the head because they didn’t have very good helmets – so the sport was largely played the way I'm describing it now,” Cantu says. “It was a great sport and I think that's what it needs to go back to.”

Trowbridge also suggests stricter enforcement of existing rules that suspend or eject a player rather than relying on fines for making illegal hits to the head or using their own head to make a hit outside of the tackle box. About half of concussions that NFL players sustained last season were caused by helmet-to-helmet hits. "Nobody should be a human battering ram," she says. "There are ways to bring down people with force and gusto without using your head as an implement."

Miller believes that the league can have it both ways – improving safety while also enjoying record attendance and revenues. “We’ve made the game safer by any number of metrics. We've seen a decrease in concussions year after year and a lot of that decrease came when we cracked down and eliminated a lot of the most dangerous hits --- the helmet-to-helmet hits and the shoulder-to-helmet hits,” he says. “At the same time, the game has never been as popular as it is today.”

The Youth Movement

Many of the most meaningful changes that remain must be implemented at the college, high school and youth league levels. While NFL players suffered 202 concussions last season, far more occurred in younger players – as many as 563 in college players and 310,000 in high schoolers, points out Dr. Jacob Resch, an expert in sports injuries at University of Virginia. Meanwhile, a 2014 Bloomberg Politics poll showed that half of Americans don’t want their sons to play football, and enrollment in the youth football league Pro Warner dropped by 10 percent from 2010 to 2012. Miller of the NFL points out that youth participation across many team sports, including basketball and baseball, has dropped by even greater amounts, as reported by the Wall Street Journal.

Cantu has said that tackle football should not be played until the age of 14 and the Sports Legacy Institute, which Cantu co-founded, has proposed a “hit count” for youth sports that is similar in concept to the pitch count in Little League that requires coaches to send in a substitute once a pitcher throws so many pitches so the player may rest his or her arm. In football, coaches would monitor the "hits" on a player's helmet and try to minimize that number over the course of a season.

Trowbridge agrees that changes to game-play should begin with much younger players. “It's got to start at a young age in terms of the techniques that are taught and that nobody is ever taught how to lead with their head and throw somebody to the ground,” she says. “If you don't know the bad way, you won't resort to the bad way.”

While Thornton believes that the NFL is taking positive steps in championing safer tackling techniques, he doubts that the game can change all that much from the way it looks today. “You're not going to sign up for the NFL not to get hit,” he says. “I don't care what position you play -- you're going to get hit pretty hard and it's going to take a toll on you at some point. That’s just how it is.”

Cantu notes that colleges and youth leagues have already adopted many of the NFL’s recent rule revisions. But unlike the NFL, youth football leagues and school athletic departments are often stretched for cash, which limits the money they have to hire athletic trainers or buy expensive tools to diagnose concussed players.

“I think the NFL and NCAA are heading in the right direction but with youth sports, I think we have a long way to go,” Resch says.

Still, more than a third of NFL fans aren’t happy with the way the league has addressed the risk of brain injury so far, according to a CNN/ORC poll of NFL fans conducted about a month after the Frontline documentary aired. As the clash between safety concerns and the entertainment value of the game continues, the league may have to contend with growing discontent among players like Chris Borland, as well as its fans.

“I'm not concerned about the game, long-term. I think they'll figure it out," Thornton says. “They'll make it as safe as possible because it's such a big business. There's a lot of people who are making a lot of money.”