As a pro football player, Martin Mayhew, being a defensive back, became used to going to work every Sunday trying to succeed with one arm tied behind his back.

Don’t let anyone tell you that the rulebook doesn’t play favorites.

In the NFL, receivers are given more benefits of the doubt than the teacher’s pet. The rules are tilted away from the defender and toward the pass catcher. It’s not enough that receivers are taller, faster, know where they’re going, and are running forward.

The pass defender is shorter, slower, has no clue which way the man he’s covering is going to juke and jolt, and he has to run backward, to boot.

Then the guys in the zebra stripes, not content with such a disadvantage, are prone to clutter the football field with yellow laundry if the defender so much as breathes on his opponent.

It’s poker with a marked deck; a carnival-midway pyramid of milk cans.

Playing defensive back in the NFL is a weekly, soul-sucking, often losing battle, mitigated only by the nirvana of defying the odds and batting a football away or, if the quarterback and the receiver are on Venus and Mars, respectively, actually intercepting a wayward pass.

Mayhew, the Lions general manager, played this game of loser’s poker for eight years in the NFL. He knows a little about working when the rules are not on your side.

It hasn’t gotten all that much fairer for him as an executive.

First, he learned the GM business by working as an underling of Matt Millen’s, which was like learning how to move a piano from Laurel and Hardy.

For years, Mayhew was Millen’s second banana, his silent partner. We knew only that Mayhew was in the organization; we didn’t really know what he did, nor did we pay much attention to him. We only thought that we knew one thing: if he was a Matt Millen hire, then how good could he really be?

Then one October day in 2008, Lions owner Bill Ford Sr. made the most overdue mercy killing since ABC canceled “Happy Days.”

Ford fired Millen, and shoved Mayhew into Millen’s seat as team GM.

Martin Mayhew! Another “MM” guy, to go along with Matt Millen and Marty Mornhinweg.

I hope we were all forgiven in our skepticism.

The tabbing of Mayhew was accepted cautiously by the fanbase, because they figured his ascension to Millen’s throne would be interim, that very sports word for “keep renting your house, don’t buy.”

Surely, the fanbase convinced itself, the Lions will wait until the end of the season and bring in a “real” GM—preferably a guy with a big name.

Bill Parcells, et al.

Now, back in the fall of 2008, the idea that Mayhew could be the long-term answer for what ailed the Lions’ front office was considered folly. Worse, it was considered incompetent and malevolent toward the fans.

The Lions were in the middle of a 0-16 season when Mayhew replaced Millen. To not go after someone outside the organization was looked at as a big old nose-thumbing by Ford to his patrons.

Yet just days after taking over from Millen, Mayhew fleeced Jerry Jones and the Dallas Cowboys of a first-round draft pick in exchange for uneven receiver Roy Williams.

It was David fooling Goliath; some kid chess player placing Bobby Fischer into checkmate.

Beginner’s luck?

The Lions played out their winless season, and then the fans rubbed their hands together. Despite the fleecing of Dallas for Roy Williams, there still wasn’t much excitement at the thought of Mayhew staying on as GM.

Not with Bill Parcells out there!

Ford did another end around, as has been his wont as Lions owner. He went against public sentiment—another Ford trait—and hired Mayhew permanently, ripping the interim tag off him like a decorated officer losing one of his stripes.

Only this was in reverse—a promotion based on little more than faith, hope and loyalty—again, another Ford-ism.

Well, guess who’s pretty good at this GM thing, after all?

Mayhew had it all going against him—just like he did every Sunday lining up against the Jerry Rices and Cris Carters of the world—yet here he is, continuing to show deftness as an NFL executive.

Mayhew had his pedigree (Millen) going against him. He had his inexperience with contract negotiations going against him. He had the Lions’ losing culture going against him.

Mayhew as brand-new GM was like one of those disadvantaged kids who is born poor to bad parents, in a home situated in a bad school district.

Perhaps Mayhew took everything he saw and heard from Millen and pretty much started doing the opposite. Whatever, it’s working.

As a player, Mayhew lived for the fall and early winter. Once, his challenge was the quick slant; now, it’s the salary cap. As a GM, this is his time to shine—his time to set the pins up for coach Jim Schwartz and his players to knock down.

From the Super Bowl in February until training camp starts in July, the NFL general manager rides a greased slope. This is the time when guys like Mayhew truly earn their bread.

The Lions are no longer stained with 0-16. They have progressed nicely under Schwartz, going from 0-16 to 2-14 to 6-10 to 10-6 and the playoffs. Just like that—like a checker traversing from one end of the board to the other.

Almost—the Lions haven’t been crowned yet.

But with every step of success comes another hurdle. The further the Lions get from their inglorious decade of the 2000s, the closer they get to the pitfalls and land mines that must be navigated through in order to make the leap from a one-week playoff run to playing in February—and I don’t mean the Pro Bowl.

Martin Mayhew seems to be the guy that can take this thing from 0-16 to the Super Bowl. He has done a marvelous job of drafting, trading, signing and re-signing.

The latter—re-signing—has been far more important to the Lions’ future than any free agent from outside the organization they’ve signed in recent years.

Mayhew wanted to keep his own free agents in the fold, and rework the contracts of some of his star players to create the financial space in which to do all that re-signing.

His off-season, thus far, has been A+.

Mayhew reworked the contracts of QB Matthew Stafford, WR Nate Burleson and DT Ndamukong Suh. He then gave WR Calvin Johnson a contract extension that makes Johnson the richest receiver in league history.

Mayhew kept LT Jeff Backus and backup QB Shaun Hill.

And, very importantly, Mayhew managed to keep MLB Stephen Tulloch for four more years, preventing him from signing with another team.

All this and it’s not even April yet.

That’s when the draft happens.

Another area in which Mayhew excels.

Who knew?