The Green Bay Packers are no longer undefeated, thanks to their 19-14 loss to the Kansas City Chiefs in Week 15. But the more important ramification of the Packers' loss is that they did not lock up home field advantage throughout the NFC playoffs.
The Packers are now 13-1, and the 49ers, at 10-3, could still earn the No. 1 seed in the NFC and the home field advantage in the playoffs that goes with it by winning out as the Packers lose twice more to fall to 13-3. The 49ers would have to win that race via a tie-breaker, but it is still possible for them.
The same can't be said for the red hot and 11-3 New Orleans Saints: though the Saints could still earn the No. 2 seed if they finish with a better record than the 49ers, their loss to the Packers way back in Week 1 means that they won't win a tiebreaker with Green Bay, even if the Packers lose twice.