The position is so pivotal, visible, difficult and mythic that most conversations about NFL quarterbacks, even some of the best, address what they haven’t done. They are rats in a maze searching for cheese being steadily pulled away from them.

The conversations revolving around Christian Ponder during training camp will cast him as a lower-tier starter, an impediment to the Vikings offense, a guy who might want to look over his shoulder when he’s not looking off the safety.

After two seasons in the NFL, and only one as a full-fledged starter, Ponder — we will hear from every NFL analyst in the country — has much to prove. That’s true, and incomplete. He already has established some important bona fides.

To insult him with faint praise, Ponder has never butt-fumbled. He has never been accused by a tabloid of dating a teenager. He has never embarrassed his organization or made himself the center of a perceived or real controversy. He has never been photographed in public wearing a baseball cap representing another NFL team.

Ponder has never shown up for camp out of shape or shown up a teammate. He is not, like so many first-round quarterbacks, a bust. He has proved he can win a close game, that he can lead a comeback, that he can win a big game, that he can ride shotgun on a playoff team even if he is not ready to be its chauffeur.

Ponder is not now and might never become a star; neither is he a punchline or a coach killer, like so many quarterbacks who are drafted in the first round.

The Vikings held the 12th pick in the 2011 draft. They not only needed a quarterback, they were sick of scouring the AARP mailing list for guys who might play one more year before becoming a spokesman for ACME Stair Lifts.

By the time the Vikings’ pick came around, Cam Newton, Jake Locker and Blaine Gabbert had been taken. The Vikings could either choose Ponder, or trade down and hope that he or another quarterback they liked would be available in their new draft slot.

Now we know that Colin Kaeper­nick was the most talented quarterback available when the Vikings picked, but his profile as a running quarterback from a smaller school made him a risk for a team that wanted immediate help and favored a traditional offense.

Essentially, the Vikings were choosing between Ponder and Andy Dalton. Dalton has been the more effective passer in his first two seasons with Cincinnati; he has also had the benefit of throwing to better wideouts, including the great A.J. Green.

After two seasons, Dalton’s quarterback rating is 83.9. Ponder’s is 77.1. Dalton has been the better quarterback, but there isn’t tremendous separation between the two, and this year Ponder will for the first time work with an accomplished downfield receiver, in Greg Jennings.

ESPN’s Ron Jaworski, the former Philadelphia Eagles quarterback, recently ranked Ponder 27th among NFL starters. Jaworski is an excellent analyst who relies on film study and deep knowledge of the position, and his assessment is on the money.

But while we’re assessing Ponder’s weaknesses, let’s also remember that when the Vikings needed to win four consecutive games against difficult opponents to make the playoffs last year, Ponder was good enough.