SANTA CLARA, Calif. -- Quarterbacks are separated by their performance in the fourth quarter.Colin Kaepernick is struggling in the final quarter during his second NFL season as a starter. In the 49ers' past two games, both narrow defeats, Kaepernick and the offense struggled in the final drives with the game on the line.According to Michael Bonzagni of ESPN Stats & Information, Kaepernick is ranked 34th among 35 eligible quarterbacks in completion percentage in the fourth quarter and beyond -- completing just 44.