Gabbert takes hit to head, replaced by Kaepernick -- who gets booed

Blaine Gabbert made his first start for the 49ers against the Falcons on Sunday, and played very well subbing for beleaguered starter Colin Kaepernick.

But in the fourth quarter, a hit to the head by Falcons linebacker Philip Wheeler forced Gabbert to leave the game and be evaluated for a concussion.

Kaepernick came in for just three plays -- two runs and an incomplete pass. The crowd reaction?

A chorus of boos for Kaepernick when he entered and left the game.