The standings have tightened up after an upset in the desert last week.
Although the early frontrunner still has a lead, two teams are close behind with a .500 record while the 49ers try to play catch up.
As San Francisco prepares to visit the New York Giants, here's what's happening around the division.
Arizona Cardinals (3-1)
Week 4: 24-22 loss to the St. Louis Rams.
Notes: The Cardinals offense, which looked like a fine-tuned machine in the team’s win over the 49ers, turned the ball over three times on Sunday.