"Because Jim Harbaugh would rather gargle thumbtacks than compare players, he didn't explain his rationale Wednesday after he announced, to no one's surprise, that quarterback Colin Kaepernick will make his third straight start Sunday when the 49ers visit the Rams.

By skirting that subject, Harbaugh didn't detail why he thought Kaepernick gave San Francisco a better chance to win than Alex Smith does. By complimenting Kaepernick, he'd be diminishing Smith, so Harbaugh instead served up some comically wishy-washy reasoning.

"What tips the scale, is Colin, we believe, has the hot hand and we'll go with Colin," Harbaugh said. "And we'll go with Alex. They're both our guys."

Harbaugh, of course, won't unveil a groundbreaking two-quarterback formation in St. Louis, but why, exactly, has he settled on the still largely unproven Kaepernick, who has two starts and 79 attempts on his resume?

Harbaugh wasn't talking much, but some numbers from Kaepernick's brief starting tenure say a mouthful about how his rocket arm and uncommon escape-ability have given the 49ers' offense a different dimension.

In his two starts, Kaepernick has been sacked just once and had five completions of at least 30 yards in 48 attempts. Smith, in contrast, was sacked 22 times in his eight full games this season. He has six completions of at least 30 yards in 217 attempts.