NEW ORLEANS — Immediately after the Super Bowl ended, there were several sad sights. One of them wore a No. 11 jersey.

Alex Smith slowly left the field after the 49ers defeat, thus ending a season in which he lost his starting quarterback job. He had watched the 34-31 loss from the sideline and now was making the morose walk to the locker room, surely his last as a 49ers player.

Or was it?

It has seemed to be a foregone conclusion that Smith won’t be with the 49ers next season. That’s because Colin Kaepernick has so obviously established himself as the No. 1 guy at Smith’s position — which supposedly means that Smith will be traded or waived during the offseason. If he’s waived, that would make Smith a free agent able to sign with any other NFL team.

But who says it will happen for certain? You can make a case that letting Smith go is not the best choice for the franchise.

In fact, I will make that case fairly vociferously.

I refer you here to the words of Jim Harbaugh — and not just the ones he uttered Tuesday. From the moment Harbaugh took over as coach of the 49ers, he has preached the mantra of his college mentor, Bo Schembechler: the team, the team, the team.

So let’s talk about Harbaugh’s 2013 team, the one that will assemble again in summer training camp. There’s no way that team will be better without Smith on the roster as a backup quarterback — if only because of the way Kaepernick utilizes his legs as such a vital part of his game.

Kaepernick stayed healthy and intact through his 10 starts after replacing Smith. But the law of averages tends to catch up with multipurpose quarterbacks of the read-option tribe.

Do you recall what happened to Washington quarterback Robert Griffin III in the Redskins’ only playoff game this season? He was hurt early in the contest and ineffective. Michael Vick of Philadelphia missed three weeks of the 2012 schedule because of injury. Both men use their feet at least as much as Kaepernick.

So if Kaepernick goes down next season — for a game or longer — whom do you want trotting out to replace him? If Smith leaves, the backup 49ers quarterback would likely be the untested Scott Tolzien, who will be in his third NFL season. Smith, who was among the NFL passing leaders before the concussion that led to his demotion, is clearly a better player than Tolzien.

So why wouldn’t the 49ers keep Smith, who is under contract for two more seasons? The arguments against it boil down to (1) the money they would have to pay him and (2) the 49ers owe Smith a favor because he has been such a good soldier since losing his starting job.

Both arguments are invalid. Smith did indeed sign a three-year contract for $24 million last March, a deal that would pay him a $7.5 million salary next season along with a $1 million bonus.

The 49ers can keep Smith on the roster if they pay him. And team executives hint that it would be possible to pay Smith the $8.5 million while still staying under the salary cap — largely because Kaepernick’s salary is about $741,000 next season and his cap is a reasonable $1.297 million. The 49ers will need to spend a little money to re-sign some other players on the current roster — but with some finagling, they can certainly handle Smith’s paycheck.

So. If money isn’t an issue, then why not hold onto the guy? Near as I can tell, it’s because Smith is a helluva guy. And he is — on the field and off.

Day after day during Super Bowl week, writers came up to Smith asking questions about whether he was bitter or angry. He deflected them all.

“This has been an amazing experience,” Smith said during one of his media sessions in New Orleans. “It’s a great team and I love being a part of it. . . . It’s a team game and a team sport. If you want it to be about yourself, go play golf or tennis. I got into team sports to be a part of a team. There’s something very unique about that, the selflessness of a team sport.”

So are we to believe that Smith is now going to suddenly become selfish? Smith is going to demand his release March 12 when the free agent period begins? And the 49ers ought to give Smith that release, just because Smith has been a good soldier?

Sorry, that’s not how the best NFL teams work, and Harbaugh said as much Tuesday when he indicated there would be no special favors granted to Smith. The best teams stockpile talent as much as possible. In the 49ers’ glory days, coach Bill Walsh and coach George Seifert kept Joe Montana or Steve Young on the bench. If Walsh and Seifert could handle the Montana/Young dynamic, surely Harbaugh could handle another year of the Kaepernick/Smith dynamic.

Sure, it would make Smith unhappy. But it’s hard to imagine him pouting and not reporting to camp. It’s not in his nature. With Smith on the squad, the 49ers would have as good a 1-2 quarterback combination as any NFL team. Isn’t that preferable?

If Smith were a different type of personality, it might be a risk to keep him around. But he’s the kind of guy who understands the NFL’s business model. Plus, did I mention he’d be making an $8.5 million salary? What’s better, life as a backup quarterback for a Super Bowl contender or life as a starting quarterback for a lousy team?

Someone from the 49ers needs to at least think about asking Alex Smith that question. And Smith needs to think hard about the answer.

Contact Mark Purdy at mpurdy@mercurynews.com. Follow him on Twitter at twitter.com/MercPurdy.