San Francisco 49ers quarterback Alex Smith (11) and quarterback Colin Kaepernick (7) warm up before an NFL football game at the Louisiana Superdome in New
San Francisco 49ers quarterback Alex Smith (11) and quarterback Colin Kaepernick (7) warm up before an NFL football game at the Louisiana Superdome in New Orleans, Sunday, Nov. 25, 2012. (AP Photo/Gerald Herbert)

SANTA CLARA -- Colin Kaepernick will make his third straight appearance as the 49ers starting quarterback Sunday, and he has grand designs on where this job promotion could take him.

"It's a great chance to lead this team, and show we're a great team that can go into the playoffs and win games," Kaepernick said Wednesday.

Rather than drag on QB Watch 2012 as he did with last week's drama, coach Jim Harbaugh announced that Kaepernick's hot hand "tipped the scales" in his favor to start Sunday's game at the St. Louis Rams.

Kaepernick assumed that role Nov. 11, when incumbent starter Alex Smith sustained a second-quarter concussion in a 24-24 tie with the Rams at Candlestick Park.

San Francisco 49ers quarterback Alex Smith (11), on left, throws the ball as quarterback Colin Kaepernick (7) watches during practice at the San Francisco
San Francisco 49ers quarterback Alex Smith (11), on left, throws the ball as quarterback Colin Kaepernick (7) watches during practice at the San Francisco 49ers Fan Fest at Candlestick Park, San Francisco, Calif., on Sunday, Aug. 12, 2012. (Josie Lepe/Staff)

"I don't know if it's a hot hand or whatever you want to call it," Kaepernick said, "but I'm just happy I get to go back out there."

Kaepernick won his first two career starts with an assortment of big plays that energized a passing attack for the first-place 49ers (8-2-1). He completed nine passes of at least 20 yards in those wins over the Chicago Bears on Nov. 19 and at the New Orleans Saints on Sunday.

Harbaugh advised reporters not to assume that this is a locked-in promotion for the rest of the season, adding: "I would assume nothing."

Harbaugh said Smith handled Wednesday's announcement like the "class act" he's always been. Smith was unavailable for comment and is expected to address the media Thursday.

The coach acknowledged that he'd be concerned if players stop reporting concussions in fear of losing their jobs like Smith did. However, Harbaugh added: "We don't fear any moment or any circumstance or any man."

Harbaugh informed his players in a team-wide setting that Kaepernick would start ahead of Smith, who led the 49ers to last season's NFC Championship Game in his seventh season with the club.

Kaepernick's arm strength, mobility and ability to thrive in read-option packages have been embraced by the offense.

San Francisco 49ers quarterback Alex Smith (11) gives a high-five to colleague Colin Kaepernick (7) after completing a touchdown pass against the San Diego
San Francisco 49ers quarterback Alex Smith (11) gives a high-five to colleague Colin Kaepernick (7) after completing a touchdown pass against the San Diego Chargers in the first half of a preseason game at Candlestick Park, in San Francisco, Calif., on Thursday, Aug. 30, 2012. (Ray Chavez/Staff)

So has his risk-taking ability, of which tight end Delanie Walker said: "That's just Kap being young, so he takes more chances. Alex is a more veteran quarterback who's controlling the offense, making sure we get another down."

Kaepernick's penchant for creating plays can be traced back, however, to his childhood role model.

"I was a Packers fan growing up, so I always watched Brett Favre and loved the way he played," Kaepernick said. "He had no fear in what a defense would do. He was going to go out there and take his shots."

In a conference call with St. Louis media, Kaepernick said his best attribute actually is his "mental game" and an ability to counter what defenses present.



"You've got the added dimension of Colin's legs," Rams coach Jeff Fisher said in comparing Kaepernick with Smith. "That's the biggest concern defensively. A couple weeks ago, he basically kept the game alive with his legs in the two-minute drill."

Wide receiver Michael Crabtree said of Kaepernick's stronger arm: "You've got to keep your eye on the ball. The guy can throw the ball real fast. It's hard, and you've got to concentrate."

Kaepernick's passing totals were nearly identical in his past two starts: 16 of 23 for 243 yards with two touchdown passes against the Bears, and 16 of 25 for 231 yards with one touchdown and one interception against the Saints. He was sacked only once in those two starts.

Smith, whose post-concussion symptoms resurfaced on Nov. 18, was medically cleared to play only a night before the game against the Saints. Since halftime of an Oct. 18 win against the Seattle Seahawks, Smith was near-perfect: 35 of 38 for 385 yards with five touchdowns, one interception and a 140.2 rating in an eight-quarter span.

Smith, an eighth-year veteran, leads the NFL with a 70.0 completion percentage and ranks fifth with a 104.1 passer rating. Smith has compiled a 38-36-1 record as a starter, with half of those wins (and a 19-5-1 record) coming since Harbaugh took over as coach before last season.

"Alex has been through a lot of tough things, and I think he'll be fine," said Frank Gore, adding that the 49ers are "cool" with either quarterback.

Kaepernick, last year's second-round draft pick out of Nevada, credited Smith for helping his progress.

"Alex has been great. Our relationship hasn't changed," Kaepernick said. "He helped me a lot last year going through our playbook, how we're going to read different things, different progressions.

"He's been a great help getting me to where I am now."

Where he'll be Sunday is facing a Rams team that surprisingly tied the 49ers after neither kicker could hit a winning field goal in overtime.

Kaepernick's thoughts on a rematch with the Rams: "I'm very eager to get back out there against them. I want to get a win this time."

Each win will help the 49ers solidify their chances at a Super Bowl run.

"We're capable of doing anything, with the defense we have and whoever is the quarterback," Crabtree said. "I'm just loving that we're trying to get into the end zone and make plays."