Could we have seen the last of Peyton Manning in a Colts uniform? (Nam Y. Huh/AP)

Some of it is focused on how his neck/back/arm will affect his value in fantasy football, which I care even less about than Arian Foster. (Foster got himself in some lukewarm water last week for tweeting that people who only cared about his injury status to the extent it affected their fantasy teams are “sick.” And he couldn’t be more right about that.) I don’t care that Peyton Manning’s neck injury projects him as the ninth pick in your fantasty football draft rather than the third, and I’d like to think that Manning, his family, his friends, the Indianapolis Colts and the Colts fans don’t care either. No, what we all should be concerned about is what this means for the “real” Peyton Manning, rather than the “fantasy” version.

Manning is listed as “doubtful” for the regular season opener this weekend. If he misses the game, it puts an end to his consecutive games played streak — which we should all care about only slightly more than his fantasy football value. According to most reports, Manning had a setback this past weekend when he suffered from some unusual back pain during his recovery from off-season neck surgery. Depending on the report you read, this could be nothing more than the aches and pains of a player rehabbing too quickly or too hard, or it could signal a more serious problem, such as a triceps problem that has taken some of the zip off his fastball and some of the length off his longer tosses. That, according to reports, could require further surgery to replace or fuse disks. And if that is so, we may have seen the last of Manning in a Colts uniform.

Assuming Manning’s injuries are minor and he only misses a few games, it changes the Colts’ season. A couple early losses with Kerry Collins under center could put them behind the eight-ball in the race for the playoffs even if Manning comes back at 100 percent to finish out the season. If Manning misses more than a few games, or if he comes back at less than 100 percent, or both, not only could a potential Super Bowl team miss the playoffs entirely, but they could end up with a losing record. Bad news for Colts fans. Great news for Texans fans, particularly since they get to play the first game of the season against the Manning-less Colts.

But let me throw something else out to you. What if this is it for Manning? What if the worst of the reports is true, he has to have some disks fused and can never play again? Or what if he can play again, but he’s the proverbial shadow of his former self?

Let me first say what should be unspoken: no one, save perhaps an old girlfriend of his, is rooting for Manning’s career to come to an end, let alone for it to end this way. But what if it is over?

The Colts will not be able to replace Manning for a long time, perhaps ever. Perhaps they play so poorly this year that they win the Andrew Luck Sweepstakes. Andrew Luck will never be Peyton Manning. Eli, perhaps. Peyton, no. It could be a long time before the Colts are ever as formidable as they’ve been in the Manning era.

And what of Manning and his legacy? If his career ends today, Manning would still earn a place on the Mount Rushmore of NFL quarterbacks with Unitas, Starr, Staubach, Favre, Elway, Montana and Brady, among others.

But we like rankings, don’t we? We want to know where he would rank all-time because that’s the way we’re wired.

Fine. Here’s one man’s opinion: were he to retire today, Manning should be recognized as the second best quarterback of all time, right behind Johnny Unitas, right ahead of Joe Montana.

For those Cowboys fans who argue that he should be ranked behind Troy Aikman, and those Jets fans who believe he should be ranked behind Joe Namath, you really need to get over yourselves.