The 49ers Attacked the 2nd Level of Philadelphia's Defense

The 49ers did whatever they wanted to on offense as they embarrassed the Eagles with a 42-19 blowout win on Sunday. There wasn’t just one thing that led to San Francisco scoring touchdowns on a staggering 6 straight drives. Their playmakers were outstanding. The offensive line won handily in the trenches. The play-calling and execution were both top notch.

But probably the biggest thing that gave the Eagles defense trouble was the 49ers’ use of motion.

Motion, especially the various ways the 49ers use it, can have a significant impact on a defense. It keeps defenders on their toes. It can make them over-reactive. It makes them have to keep track of more information on the fly, like gap responsibility in the run game and receivers to match up to in zone coverage, both of which can change with motion. It forces defenders to be perfect with their communication and understanding of shifting responsibilities.

The 49ers used motion relentlessly to manipulate Philly’s second-level defenders and take advantage of their depleted linebacking corps on Sunday. They were able to create spacing in the passing game and angles in the run game. They used it to influence Eagles defenders on misdirection plays. They set up tendencies using motion that could then be broken at the right time for big gains.

Below are some examples.

First, let’s take a look at the 49ers’ initial 3rd-down of the game. This was a 3rd-and-12. Running back Christian McCaffrey aligned offset to Brock Purdy’s right and then motioned out to the slot before the snap. Linebacker Nicholas Morrow followed in man coverage:

McCaffrey would end up running his route right at the first-down marker. On this snap, the pressure would force a rushed throw and an incompletion, and the 49ers would be forced to punt:

Later in the game, however, the 49ers faced a 3rd down from the Eagles’ 45-yard line and made a slight tweak.