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San Francisco 49ers' starting quarterback Colin Kaepernick (7) scrambles against Chicago Bears' Stephen Paea (92) in the second quarter at Candlestick Park San Francisco, Calif. on Monday, Nov. 19, 2012. (Nhat V. Meyer/Staff)

The historical landscape of sports is strewn with nanosecond careers of young men whose introductions were followed by rose petals and the sound of trumpets. They flash, they dash. It happens in every sport, perhaps none more than the NFL.

That is not to say 49ers quarterback Colin Kaepernick is destined to be the next comet.

That is to say one start, no matter how extraordinary the performance, is hardly a fair or accurate gauge of what should be expected on a consistent basis.

Kaepernick's starring role in San Francisco's 32-7 exposing of Chicago's paper Bears raised the ante. What once was a quarterback curiosity is now a full-fledged competition. A controversy, if you will, between Kaepernick and incumbent Alex Smith, exacerbated by coach Jim Harbaugh claiming each has a "hot hand."

Kaepernick proved himself capable of undressing an NFL defense. Chicago's defense is of dubious quality -- though we can conclude it was overrated. Still, the unit has some very good players, and they appeared helpless against the passing and scrambling skills of the second-year NFL athlete from Nevada.

At the least, Kaepernick earned the opportunity to start Sunday in New Orleans, when the 49ers face the resurgent Saints. It's another test, a bigger test insofar as road games in domes present particularly difficult challenges for a quarterback.

Though he deserves another start even if Smith receives medical clearance -- it's not possible for an NFL team to be too cautious in the wake of a concussion -- it's premature to promote Kaepernick as ready to replace Alex in the starting lineup.

I'll offer a couple examples why the job, for now, still must belong to Smith -- and why it's always dangerous to fall for a quarterback after only the briefest of glimpses.

We don't have to look very far for the first: Troy Smith. Remember him, the Heisman Trophy winner from Ohio State? He signed with the 49ers in 2010, eventually moving up from third string to become a starter in the wake of an injury to Alex Smith.

Troy Smith won his first start in San Francisco with a dazzling comeback over Denver and after winning his second by throwing for 356 yards to beat the Rams, then-coach Mike Singletary said: "It's like watching Brett Favre.''

No, it wasn't. Not after opponents dissected Troy's game. Not after Troy lost a couple starts. Troy Smith tumbled back to earth and, ultimately, out of the NFL.

Another deceptive performance, perhaps the most famous of all, is that of Clint Longley. On Thanksgiving Day 1974, he replaced injured Dallas starter Roger Staubach and carved himself into Texas legend, leading the Cowboys to a comeback win climaxed by a 50-yard touchdown to Drew Pearson in the final minute.

Longley threw two TD passes that day. He threw five in his entire NFL career.

A more recent example of a quarterback launching himself to "stardom'' after one great game is Matt Flynn, formerly of Green Bay. In his one start last season, he threw for 480 yards and six touchdowns in a 45-41 victory. That was enough to convince Seattle to hand the free agent a contract worth $26 million, $10 million guaranteed.

Flynn failed to win the starting job in training camp and has spent this season cashing fabulous paychecks while sitting behind rookie starter Russell Wilson.

No NFL franchise has completely avoided a cautionary tale involving a quarterback who delivered a misleading performance that fooled the front office -- and the fans.

I believe Kaepernick has a bright future, almost certainly in San Francisco. He has the physical tools and the mental toughness. He can thrive under the tutelage of Harbaugh and the wizardry of offensive coordinator Greg Roman.

Moreover, Kaepernick already exhibits something Alex Smith never has: swagger.

Did you see how he sprinted toward the end zone after firing a dart that Michael Crabtree caught for a touchdown Monday night? Kaepernick faced the receiver, locking eyes with him, and briefly partnered with Crabtree for a celebratory dance.

Now that was a moment that looked like something from the book of Favre.

Alex Smith is a very good quarterback, efficient and so smart that the humming of his brain can be heard three miles away. He has started 75 NFL games, and it was just last season that he was at the controls of a 13-3 team that reached the NFC Championship game.

Kaepernick is one start into his promising NFL career. It was a superb start, enough to fire up imaginations throughout the fan base.

But his NFL background remains sparse, his references practically nonexistent. He is mature enough to recognize one game does not constitute a "hot hand.''

Just remember, history is great at reminding us to be careful of falling in love with an athlete at first sight. What you think is a star might be a comet.

Contact Monte Poole at mpoole@bayareanewsgroup.com. Follow him on Twitter at twitter.com/1montepoole.