In the past week, the first three NFL seasons of Blaine Gabbert's and Colin Kaepernick's careers have been compared often.The 49ers acquired Gabbert from Jacksonville for a sixth-round pick last week and Gabbert is poised to be Kaepernick's backup this season. Gabbert was the 10th overall pick of the 2011 draft, while the 49ers took Kaepernick with the No. 36 selection.Kaepernick has had much NFL success in fewer than two full seasons as a starter, while Gabbert has struggled and is not considered a starting-quality player.