After the game, Kaepernick insisted he scored.
The NFL's vice president of officiating, Dean Blandino, told NFL AM on Monday that there was no definitive view showing Kap crossing the goal line with the ball that could overturn the ruling.
"Kaepernick goes into the pile, the umpire sees the ball loose, he has 55 on St. Louis recovering the loose ball," Blandino explained. "It went to review, we looked at it. There's one angle from behind the defense where you can see Kaepernick going toward the ground, the ball does come loose, but you never saw a body part like an elbow or a knee down prior to that. It was impossible to tell where the ball was in relation to the goal line before it came out, so again, the ruling on the field stood.
"The evidence just wasn't definitive either way, and that's why the call stood as called."