The question has Mark Brunell stumped, a riddle he is attempting to sound out on the fly. Where have all of his people gone?

No, we are not talking about middle-aged University of Washington alumni or former NFL players now doing football commentary for ESPN. Folks from those castes are easy to find.

This discussion centers around left-handed quarterbacks. Or the obvious current shortage of them at the NFL level.

Brunell, a left-hander who spent 19 seasons with the Packers, Jaguars, Redskins, Saints and Jets, is curious about the topic but unable to guarantee an explanation.

“It’s hard to say there is one major factor at play,” he says. “But unfortunately, we’re a dying breed. We need someone to relight and carry the torch for us. If we don’t find that, we could become extinct here soon.”

Here are the hard numbers worth exploring. With a multitude of studies approximating that 10 percent of the general population is left-handed, it would seem reasonable to assume the percentage of left-handed quarterbacks at all levels would fall in a similar range.

Yet with NFL training camps underway, out of the 120 quarterbacks currently under contract, only two (1.7 percent) are left-handers.

They are Kellen Moore, a fourth-year backup with the Detroit Lions who has never thrown a regular-season pass; and Tim Tebow, signed by the Philadelphia Eagles in April as a gadget player after spending the last two seasons out of football.

Last season, 72 NFL quarterbacks threw 17,845 passes during the regular season and only 121 came from a lefty, all launched by Michael Vick with the New York Jets.

And over the past five years, 55 quarterbacks have been selected in the NFL draft. Not a single one has been a southpaw.

Is this collection of data strong enough to classify left-handed quarterbacks as an endangered species? Is it a telling trend, a confirmation of bias? Or is it simply coincidence?

After all, there never has been a surplus of left-handed quarterbacks in the NFL. Only a few dozen have ever become starters, and Steve Young registers as the only one among modern-era quarterbacks enshrined in the Pro Football Hall of Fame, alongside 22 of his right-handed peers.

Former Georgia quarterback David Greene, a lefty who made 51 college starts from 2001 to 2004, knows the viable theories that bounce around — that many coaches and offensive coordinators prefer to construct their systems and game plans for righties; that protecting a left-handed quarterback’s blind side with a right tackle can present greater challenges; that receivers sometimes struggle with the spin on a lefty’s passes. But Greene cannot say any of that ever inhibited his climb, from his high school days in Georgia through his time excelling in the SEC to his brief professional bounce-around during which he never threw a pass for the Seahawks, Patriots, Chiefs or Colts.

“Right now,” Green says, “I’d just guess that this is a low point in a cycle that will come back around eventually.”

Receiving rapport

Jeff Christensen is certain he has at least part of the answer for the current shortage. A former NFL quarterback who was a fifth-round pick by the Cincinnati Bengals in 1983, Christensen runs and leads Throw It Deep, a quarterback and receiver training academy in the Chicago area. In rough numbers, Christensen said he is instructing 150 quarterbacks across all levels. Yet whereas in recent years he would have 15 to 20 left-handers, at present he is tutoring only seven.

Part of the decline, Christensen is convinced, can be traced to wide receivers, the particular playmakers who like passes to settle into their hands with few complications. Yet lefty quarterbacks deliver a ball that spins differently from what most receivers are accustomed to seeing.

Suddenly, rapport becomes harder to build.

“I truly believe the receivers drove the train in this whole deal,” Christensen theorizes. “At the top, big-money receivers got more of a voice. And it filtered down to college, then down to high school and down below that.”

Christensen’s most notable work with a left-handed quarterback came with his son Jake, who won the IHSA Class 8A state championship at Lockport (Ill.) in 2003 and went on to become a starter at both Iowa and Eastern Illinois.

Jake Christensen believes there is something to his dad’s theory.

But, says Jake, “I don’t think a coach would ever have a scenario where it’s, ‘Look, I have this left-handed quarterback who is obviously much better than my right-handed quarterback. But I’m going to play the righty because the receivers like his ball more.’ Still, the spin can lead to more drops. And if at the end of the day you have a righty with a 65 percent completion percentage and you have a lefty at 57 — even if the difference is based almost entirely on drops — that can affect a coach’s thought process.”

The spin complaints are familiar to Brunell and Greene. On deep balls in particular, both quarterbacks acknowledge that a left-hander’s passes will turn over and tail left instead of right at the end, requiring an adjustment. But is that a huge deal?

For Brunell, there was one easy way to classify the guys who complained about the spin or trajectory of his passes.

“Those were the receivers who weren’t very good receivers,” he says. “The really good ones I was around — Jimmy Smith, Keenan McCardell, Santana Moss — they could just catch. It didn’t matter who the ball was coming from.”

Adds Greene: “I’d always shoot back, ‘Your job as a receiver is to catch the football. It’s not to catch a right-handed ball.’”

Baseball rewards lefties

In league circles, talent evaluators readily admit they take note of the needed adjustments for receivers when assessing left-handed quarterbacks. But the spin of a quarterback’s passes is only one tiny box way down a long checklist of prioritized traits.

In other words, most general managers would not pass up a top-tier quarterback based solely on the arm he throws with. So the current shortage of lefties might be little more than the result of a small sample size.

For what it is worth, football was not the only sport in which Brunell was drafted. When he was 21, baseball’s Atlanta Braves saw an athletic lefty with a strong arm and selected him as a pitcher late in the 1992 draft.

“And I wasn’t even that good,” Brunell says.

So there has to be something to the notion that many talented, young, strong-armed lefties naturally navigate more toward baseball, the craft that seems to reward left-handers more handsomely than any other.

“Let’s face it,” Greene says, “if you’re a left-handed kid with a strong arm when it comes to baseball, you’re probably sitting at the table with more poker chips. If you throw high 80s (mph), low 90s, they’re going to give you every chance in the world for things to work out.”

While Greene feels confident that a handful of elite lefties eventually will help alter the numbers in the NFL, Jake Christensen wonders whether the current scarcity may create a self-fulfilling prophecy that the species is indeed endangered.

“The numbers have to be a deterrent at least somewhat,” he says. “If you’re a left-handed kid, who do you emulate? Who do you want to be like? And when all you see is right-handed quarterbacks, you may just inherently think that lefty quarterbacks don’t have a shot, that they don’t make it.”

If that theory holds water, tangible hope will be needed to inspire the next generation.

Currently, Notre Dame junior Malik Zaire and Michigan junior Shane Morris register as the most prominent lefty starting quarterbacks in college. But how far either player advances remains to be seen. So, for now, it is difficult to forecast even a small resurgence of left-handed quarterbacks.

“I suppose it’s just the reality right now,” Brunell says. “Unfortunately, I’m not sure there’s a clear-cut solution.”