Who would have the arrogance and madman guts to bench a playoff-tested quarterback in his prime in the middle of a go-for-broke season?

Jim Harbaugh and the 49ers, of course.

Who would have the gall or the genius to turn the offense over to Colin Kaepernick after a single breathtaking start, which he got only because Alex Smith was sidelined with post-concussion symptoms?

You know who.

Surprise! Harbaugh simply isn't anything like other coaches or regularly cautious humans, and if you needed more evidence, SI.com's report that Harbaugh has decided to go with Kaepernick for Sunday's game should do it.

According to Jim Trotter's report, Smith has been informed that Kaepernick will start in New Orleans and that the decision does not involve Smith's health status.

The 49ers have done nothing to dispute the essence of this, by the way, other than offensive coordinator Greg Roman mildly saying Thursday that "no decision has been made" at QB.

There was no other way for the 49ers to handle this, since every Harbaugh signal from the minutes after Kaepernick's landmark performance against the Bears on Monday night pointed to this, anyway.

Kaepernick was last year's high draft pick by Harbaugh and general manager Trent Baalke, he was the long-term plan when the 49ers chased Peyton Manning last spring and he was shoved into games early this season even when Smith was playing well.

Kaepernick was always the future, with an expected 2013 arrival time. Then Smith's untimely injury plus Kaepernick's incredible display moved up the timeline.

This job -- and this team -- is apparently now Kaepernick's to lose.

Frankly, despite Smith's career-best stats, Harbaugh probably didn't want to hesitate with Kaepernick and then possibly live to regret it in the playoffs.

Also, I'm guessing the 49ers want to know right now what they have in Kaepernick.

San Francisco 49ers’ Colin Kaepernick  takes on the Chicago Bears in the first quarter at Candlestick Park in San Francisco, Calif. on Monday, Nov.
San Francisco 49ers' Colin Kaepernick takes on the Chicago Bears in the first quarter at Candlestick Park in San Francisco, Calif. on Monday, Nov. 19, 2012. (Susan Tripp Pollard/Bay Area News Group) ( SUSAN TRIPP POLLARD )

Is he an instant franchise QB or will they need to make other plans, possibly including a move back to Smith?

Better to get that settled now, I guess, if you're a madman coaching staff.

I think this is a premature move, and I think Smith deserves to keep this job.

But coaches have to go with their instincts -- timid coaches are losing coaches -- and the 49ers' staff apparently has locked into Kaepernick.

Of course, making this kind of change in late November is gutsy, but it lets Harbaugh, Roman and Kaepernick figure things out in time for the playoffs.

Still, this all has to be a jolt for Smith, who is losing his job for, what, the fourth or fifth time in his eight-season 49ers career?

But remember, it was Harbaugh who committed to Smith last season when he could've come into this job demanding anybody but Smith.

And it was Harbaugh who coached Smith into the QB that he is now: 70 percent completion rate, solid leader, dependable winner in almost every way.

If Harbaugh has decided that Kaepernick's internship is over, then I don't know how loudly Smith can complain.

And we know Smith. He might not agree, but he probably understands all of this, has seen it coming, and will not stage a public pout.

Harbaugh says that the NFL is about high-stakes competition, and though he occasionally excerpted Smith from that conversation, it was always in the background at QB.

Kaepernick challenges defenses in many more areas, he's younger, he's much more dynamic, and the locker room was electrified by him.

So when Harbaugh graded Kaepernick's performance as an "A-plus-plus" on Wednesday and then equated Kaepernick's small sample size to Smith's last season-and-a-half. that was a cardplayer's "tell."

Maybe the biggest indicator: While most of us assumed the 49ers would put Kaepernick primarily in safe, run-first situations, Harbaugh & Co. launched Kaepernick as a pure drop-back QB.

And Kaepernick flourished, against a very good Chicago defense, with the knowledge that he could always break off a long run if necessary.

Instead of doing less with the offense because Kaepernick was in, the 49ers did more with No. 7.

Again, it's risky to do this now. If Kaepernick bombs out, Harbaugh could look extremely rash and mostly foolish.

It's possible that, even if the 49ers turn back to Smith later this season, the chemistry and confidence will be gone.

It all could backfire on a team that otherwise seems ready-made for another long playoff run.

So yeah, there might not be another coach or team that would dare to do this.

But Harbaugh has proved that he doesn't care about public-relations implications or potential blowback.

Probably in the back of his mind, the riskiness of making this change was part of the allure too. When you're an NFL madman, how you could you resist?

Read Tim Kawakami's Talking Points blog at blogs.mercurynews.com/kawakami. Contact him at tkawakami@mercurynews.com.