SANTA CLARA – Jim Harbaugh went with the hot – and bold – hand over the safe and steady one Wednesday, choosing Colin Kaepernick over Alex Smith as the 49ers' starting quarterback Sunday at St. Louis.

"Both have earned it. Both deserve it," Harbaugh said of the starting job. "Alex over a long period of time; Colin by virtue of the last three games. What tips the scale is Colin, we believe, has the hot hand and we'll go with Colin."

Kaepernick, the second-year player from Turlock, will make his third start of the season. What's different this week is that Smith, who recently recovered from a concussion suffered Nov. 11, is healthy as the 49ers practice for Sunday's game.

Harbaugh was asked if Kaepernick is the permanent starter rather than merely the starter for the upcoming game.

"I wouldn't assume anything," Harbaugh said. "I know you probably will, but I would assume nothing."

Harbaugh offered few specifics for why he picked Kaepernick over Smith, the former No. 1 overall draft pick who was 6-2 before his injury and having the best season of his career.

However, a dichotomy has begun to emerge between the quarterbacks.

Kaepernick hasn't hesitated to push the ball downfield and is averaging 9.2 yards per pass attempt. That's more than any starting quarterback in the league, nearly a yard more per attempt than Carolina's Cam Newton (8.24 yards) and Washington's Robert Griffin III (8.21).

Kaepernick has six pass plays of 30 yards or more on 74 attempts this season. Smith has six 30-yard-plus plays on 217 attempts.

Kaepernick's family is from Wisconsin, so naturally he grew up rooting for the Green Bay Packers and their quarterback at the time, Brett Favre.

"I loved the way he played the game," Kaepernick said. "He had no fear of what the defense was going to do. He was going to go out there and take his shots."

Asked if he considered himself a gunslinger like Favre, Kaepernick demurred: "That's not for me to say."

Kaepernick's teammates, however, believe he plays without fear, much like Favre. Several raved about Kaepernick's composure Sunday in the deafening New Orleans Superdome, especially the way he converted third-and-long situations.

Tight end Delanie Walker said Kaepernick isn't afraid to take risks.

"That's just Kap being young, so he takes more chances," Walker said. "Alex is the more steady quarterback, controlling the offense, making sure we get another down. Kap, he will take a chance and go for the big play."

Smith has been described as the anti-Favre, a quarterback who has excelled because of careful decision-making rather than derring-do.

"He is a guy that, until he understands (an offense), he is non-functional," Urban Meyer, Smith's coach at Utah, said in 2005. "He is a guy that – I keep hearing how Brett Favre kind of makes something out of nothing and is a person that runs around to make a play. Alex Smith is not that kind of player."

Last year, Smith threw only five interceptions in 18 starts. This year, he had been averaging 7.98 yards per attempt, fourth in the league and easily the highest of his career.

That average is largely due to Smith's efficiency. His 70.0 completion percentage tops the league, and his 104.1 passer rating ranks fifth.

Smith did not speak with reporters after Harbaugh's decision, which was announced to the team at the morning walk-through. A spokesman said Smith would be available today.

Instead, running back Frank Gore, who entered the league with Smith in 2005, spoke for the quarterback.

"Alex has been through a lot of tough things," Gore said. "I think he'll be fine. I know the guy loves the game. Alex loves to play football. That's tough. But coach (Harbaugh) made the decision, and that's what we've got to go with."

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