Head football coaches don’t die, they just fade away — and re-emerge as assistants.

The NFL is filled with them; former head coaches who couldn’t make it as the Boss Man, but who are nice and comfy sitting upstairs, radioing plays down to the field, or standing next to the Boss Man on the sidelines, barking out orders to his narrowed down group of charges.

There’s no shame in being a failed head coach in the NFL. Only 32 men hold that title at a time, and that is supposed to mean that they are 32 of the very best coaches in football, for one reason or another. It also means that others should get the opportunity to show why they’re one of the Top 32 whenever one of the thirty-two stumbles. But there is no shame in failure, because it’s a damn hard job to do.

The coordinators and position coaches who find themselves as the Boss Man sometimes are overwhelmed by the task at hand. They find that it’s a whole different ballgame when you’re accountable for EVERYTHING.

I believe that Rod Marinelli is overwhelmed.

He just doesn’t have the chops for this head coaching thing. From game management to clock management to officials challenges to personnel decisions, he doesn’t make the grade. This isn’t news, I know. But all I mean to say is that if it turns out that Rod Marinelli is a very good position coach and not a very good head coach, then so be it. No hard feelings. Just part ways with him and find someone else. And if Marinelli resurfaces elsewhere as a d-line coach, terrific. Good for him. I mean it.

Look at the Philadelphia Eagles and who’s calling their offensive plays. It’s none other than our old friend, Marty Mornhinweg. Now, I must confess that my blood pressure shoots up a tad whenever I see Marty on the Eagles’ sidelines, because I thought he was a poor pick from the get go as Lions head coach. Matt Millen was enthralled by Marty after one interview and late night film session, and hired him on the spot, before Marty could get on a plane bound for Cleveland to talk to the Browns. Not the way a rookie team president should hire his first coach.

But like I said, the league is filled with them. Failed head coaches — and by failed, I mean no Super Bowls, because that’s pretty much the measuring stick anymore — who have settled in nicely as coordinators or position men. I’m sure that their stints as Boss Men might eat at them a bit — whether because they don’t feel they were given enough time, or enough talent, or enough of both, or whether they just feel that they disappointed themselves in their performance. But there they are, still in the league that they love, doing what they love doing: coaching football players.

Marinelli is a football coach. No question about that. He’ll do it for as long as they’ll have him. But he’s not a head coach, and so we found that out so move on.

“Sorry it didn’t work out.” That’s pretty much all that needs to be said. No sense bad-mouthing him as he heads out the door. No reason to dog him. No name calling. It didn’t work out. We move on.

I was fooled — and it wasn’t the first time, certainly. I believed Marinelli to be the right man, finally, for the Lions head coaching gig, sometime during the summer of 2006 as he conducted his first training camp. I actually liked his introductory presser, though I know that’s not necessarily a good portender of things to come. But I liked that he came from the trenches and believed in the importance of the trenches — on both sides of the line of scrimmage. He talked like a military man. His opening words to the press were, “Good morning, men.” It was like he was addressing the troops. And I liked that.

But it didn’t work out. Not even close.

No Lions head coach has left the team with a career winning record in Detroit since Joe Schmidt resigned in a huff after the 1972 season. Well, that’s not entirely true. Gary Moeller was 4-3 in relief of Bobby Ross before Millen cast Mo aside for Marty. Schmidt was 43-34-7 as Lions head coach from 1967-72. Such a record today would thrust the coach into the driver’s seat in the Detroit mayoral race. Maybe even make him a favorite to succeed Jennifer Granholm in Lansing.

The Lions, most assuredly, will be looking for a new head coach come January. They have to. Marinelli cannot be kept on after this potentially history-making season. His career record in Detroit is likely to be either 11-37 or 10-38. You can’t be among the Top 32 in anything with a success rate like that.

Marinelli didn’t work out, so when the Lions let him go, I hope we don’t kick him between the back pockets on his way out. I hope we don’t mock him. Because unlike some of the stiffs who’ve passed through here, i.e. Darryl Rogers, at least Marinelli gave a damn. At least he believed in himself. He probably believed in his players a bit too much, and protected them too much, but as maddening as it was to us at times, he didn’t change his message.

But I’m sure there’ll be cracks about “pounding the rock” and “digging for the light” and all that, but let’s just move on. Hire a new front office team, look for a new head coach, and look ahead. Lord knows we’ve done enough looking behind us when it comes to the Lions.