SANTA CLARA – "He's going to be famous one day."

Colin Kaepernick's great grandmother, Ada Klatt, made everyone in the room stop and turn when she uttered those words in 1988. Family members reacted with polite laughter. After all, the baby boy she had in her gaze was just a few months old.

Klatt was 84 and in declining health, and she would pass away just a month and a half later. But she was certain of what she said.

"No," she said more forcefully this time, making the room go silent. "He's going to be famous one day."

That scene has been a part of Kaepernick family lore, and it has been recalled over and over this week as Kaepernick readies for the biggest stage of his life.

Today's divisional playoff game between the Packers and 49ers has plenty of story lines, none juicier than the duel between Kaepernick, San Francisco's still-learning quarterback, and Green Bay's Aaron Rodgers, the league's MVP a year ago.

Coach Jim Harbaugh gambled when he made the controversial decision to go with Kaepernick over Alex Smith, who beat Rodgers and the Packers in Week 1.

Win today, and the 49ers advance to the NFC Championship Game, the same stage they reached with Smith last year, and Harbaugh's gamble will be justified. Lose, and there will be an avalanche of second-guessing, and Harbaugh's standing, currently at platinum levels in Northern California, will take a hit.

Is that too much pressure for a quarterback who has started just seven games and, at 25 years and two months old, is the youngest 49ers passer to start a playoff game?

Nah, say family members and teammates. Nothing ever has seemed too big for Colin Kaepernick.

"It's hard to explain," said his brother Kyle, who is 10 years older than Colin. "But there was always something different about him. In the big moments, he always rises slightly above everyone else."

Kaepernick's ability to handle pressure is what landed him in the spotlight today.

As the 49ers' Week 11 game – on "Monday Night Football" against the Chicago Bears – approached, there was little doubt inside the organization that Smith, knocked out of the previous game with a concussion, would start.

His symptoms had quickly gone away, and he had passed nearly all of the post-concussion steps for returning. He had taken all of the starter's practice repetitions that week.

But on the Sunday before the game, Smith's symptoms returned. The 49ers were forced to turn to Kaepernick, who never had started an NFL game and had just a day and a half to prepare for a Chicago defense that was as hot as any at the time.

The result: two touchdowns, a 133.1 passer rating and a 32-7 win.

"Anytime a guy can come in and lead like that – and I don't mean verbally but leading by example – is what we as football players look for in a player," wide receiver Randy Moss said. "Especially in a quarterback."

Guard Alex Boone said when Kaepernick entered the huddle for the first time in the Bears game, he looked at his veteran teammates and said, "All right, ladies, let's do this."

Kaepernick seemed equally undaunted this week.

Harbaugh described the quarterback's preparation as "savant-like." Even Smith has been impressed with Kaepernick's cool.

"The closer to game day, he keeps to himself and mentally prepares," said Smith, adding that Kaepernick blocks out the noise – literally – with red headphones that always are perched atop his head. "He's making sure his mind is right. At least that's what I think he's doing. He's locked in."

Plenty has been written about the "chip" that Rodgers will bring today in his first non-preseason game in San Francisco.

Rodgers, a Chico native who grew up wearing a Joe Montana jersey beneath his uniform, was stung when his beloved 49ers bypassed him in favor of Smith with the No. 1 overall pick in 2005. Rodgers reportedly has questioned Green Bay coach Mike McCarthy, then the 49ers' offensive coordinator, about the decision more than once, and shortly after the draft, he vowed to bring a convoy from Chico to Candlestick Park the first time he played there.

Kaepernick also is propelled by a perceived draft-day slight, Kyle Kaepernick said.

Kaepernick threw for more than 10,000 yards at Nevada and was impressive at the 2011 scouting combine. Tests showed he had the strongest arm of all the quarterback prospects – including No. 1 overall draft pick Cam Newton – and one of the sharpest minds.

But on draft day, Kaepernick watched as five other quarterbacks were taken before the 49ers selected him in the second round.

He hasn't forgotten, his brother said.

"I don't ever want to see the same look on his face that I saw when the first round ended," Kyle Kaepernick said. "He was not happy."

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by Matthew Barrows

Order Reprint