When San Francisco 49ers linebacker Patrick Willis, a five-time All-Pro selection, announced his retirement due to health and injuries Tuesday — only six weeks after his 30th birthday — yet another challenge was issued to the Pro Football Hall of Fame selection committee.

As if by reflex, fans and social media immediately responded to Willis’ announcement by declaring his career to be that of a Hall of Famer — or not. But they must all wait at least the required minimum of five years before the actual selectors can cast votes on Willis — or not.

Meantime, The Sports Xchange took a survey of the 46 current selectors. They were asked to rate Willis’ worthiness for the Hall of Fame on a scale of one to five, with one being no way and five being a slam dunk.

Based on returns from 30 selectors, the result was, well, interesting. We will get back to that.

When the real voting takes place in five years, decisions of selectors will be complicated by a growing list of considerations.

With the National Football League itself emphasizing a more enlightened approach to safety, injuries and domestic violence, selectors are woefully under-equipped to make a responsible decision on a player’s HOF-worthiness based solely on a single mandate — consider only his accomplishments on the field.

For almost 25 years as a selector, I wrestled with how to properly and fairly evaluate a player based only on that single rule. As if that were not difficult enough, the process is now increasingly impacted by the rapid progression of new and dramatic dynamics.

Against a backdrop of massive legal suits by former players with lingering physical issues, should a player who is obviously on track for the Hall of Fame be devalued for not hanging in there a few more seasons?

And how should a player’s HOF-worthiness be perceived if he is subjected to punitive action by the league for something that took place far away from the field?

On the health issue, Willis joins former wide receiver Sterling Sharpe and running back Terrell Davis among players whose accomplishments were extraordinary, but concessions to health concerns prematurely interrupted those careers that were pointing straight at Canton, Ohio.

As for off-the-field situations, Minnesota Vikings running back Adrian Peterson, whose on-field accomplishments are already legendary, was sternly admonished by the league for the manner in which he disciplined his son at home in Texas. Peterson was banished from the game for one season, a punishment far more punitive than that issued by the judicial system itself.

While on the field, all the aforementioned players — Willis, Peterson, Sharpe and Davis — absolutely displayed Hall of Fame ability. Based on only that, as the sole instruction states, they belong in the Hall of Fame. But the reality is, evaluations will be impacted by their longevity and, perhaps, behavior away from the field.

In an emotional press conference, Willis made it perfectly clear that he was walking away from the game while he can still walk.

“If I had anything left in these feet — you’ve all seen me, I broke my hand on a Sunday, had surgery on a Monday and played with a cast on Thursday — but it’s something about these feet,” Willis said. “When you don’t have feet, for me, that’s what has made me who I am.”

On the field, those feet made Willis an All-Pro in five of his first six seasons. He is one of only six modern-era players with that many All-Pro selections before the age of 30. He collected at least 100 tackles in six of his seven seasons before playing in only four games last year.

But, so far, only six modern-era players were voted into the Hall of Fame with fewer than 10 seasons of play — Gale Sayers, Earl Campbell, Lee Roy Selmon, Dwight Stephenson, Lynn Swann and Kellen Winslow.

Of those, only Campbell played as many as nine seasons. And the great Tyler Rose is paying dearly for those years as he now gets around only with the help of a walker.

Despite being armed with only one vague rule, perhaps the selectors’ perspective will evolve, much as the game itself.

Just last February, Davis was a HOF finalist for his achievements during only seven seasons with the Denver Broncos, including one in which he rushed for 2,003 yards. But he was forced into retirement by injuries and headaches.

This week, Willis was given a thumbs up in that TSX survey of selectors, averaging a solid 3.5 out of a maximum five.

Perhaps spurred by all this, one veteran of HOF selection meetings strongly suggested that Sharpe should get his due for the three All-Pro seasons in a tremendous seven-year career (1988-94). The Green Bay Packers receiver averaged 78 catches, 1,162 yards and 9.2 touchdowns, all before major rules changes that made life safer for receivers. But Sharpe’s career ended swiftly in 1994 due to damaged vertebrae in his neck in his final two games.

These proud players don’t dwell aloud on what might have been, but they understand their precarious position in history and in relation to the Hall of Fame.

“I told my dad this earlier; people talk about the Hall of Fame and all that good kind of stuff and don’t get me wrong, the Hall of Fame to me would be amazing to be inducted into the Hall of Fame,” Willis said Tuesday.

“I went and approached the game, every year I said to myself, ‘if I’m going to be in the Hall of Fame someday then I’ve got to play like it, right.’ So, if I only just continue to be OK, be OK, be OK, and then all of a sudden my last year, I have an amazing year and now that’s enough to get me to the Hall of Fame, I’m not like that. I want to be continuously great, from the time I come in from the time I end.”

So now the wait begins for Willis and continues for Davis and Sharpe. The mood of the selection committee does indeed seem to be swinging in their favor, but because there are so many worthy players knocking on Canton’s door, nothing is easy.

As for Peterson, Talk of Fame Network’s Clark Judge took a poll of his fellow HOF selectors, asking if the great running back was still a strong candidate for induction despite the suspension. The answer was an overwhelming yes.

Judge reminds that former Green Bay running back Paul Hornung was suspended for a year for gambling but he eventually made the Hall of Fame. It wasn’t easy as Hornung was a finalist 12 times before being allowed in.

Peterson has a ways to go, too. He may need to substantiate his pre-suspension greatness on the field. Then, five years after he leaves the game on his own terms, the five-year clock will start.

Until then, the jury is out.

–Frank Cooney, founder and publisher of The Sports Xchange and NFLDraftScout.com, is in his 50th year covering football and is on the Pro Football Hall of Fame Selection Committee.