Kaepernick struggled vs. top defenses

SANTA CLARA, Calif. -- Quarterback Colin Kaepernick had his worst NFL game against the Carolina Panthers two months ago.

But that might not be what most concerns the San Francisco 49ers heading into their divisional playoff game at Carolina on Sunday. The game against the Panthers was just part of the problem. Kaepernick struggled against the league's better defenses in general throughout the 2013 regular season.

Against the teams ranked in the top half of the NFL in Opponent Total QBR, Kaepernick led the 49ers to a 3-4 record. Against the bottom half, Kaepernick and the 49ers were 9-0.

He threw 18 touchdowns and no interceptions to the bottom teams, while he threw seven touchdowns and all eight of his interceptions in the seven games against top-notch opponents. His total QBR against the porous defenses was a whopping 91.2 -- the best in the NFL. Against the best defensive competition his Total QBR was 31.2, which was 24th in the league.

What does this all mean? There are many variables and not all of the reasons for the poor play are on Kaepernick. Still, there is no doubt going into this game, he does have some improving to do against elite defenses.