One of the joys of beginning another Kansas City Chiefs season is seeing the new offensive wrinkles head coach Andy Reid shows us. He loves to come out firing before laying back on his best calls — and then peaking in the playoffs. Historically, these new tricks and play-calling gadgets have allowed Reid’s teams to be dominant in September.

Let’s examine two new wrinkles we saw in Thursday’s season-opening 27-20 victory over the Baltimore Ravens.

I saw the 49ers use this weird RB motion last year with CMC, and we saw Reid do it this week, weirdly from Under Center. Pacheco floats out, and Ravens struggle to pick up the late release. Not sure what cov is here, but motion gets Pacheco up rail fast pic.twitter.com/Y55Ul6IA3k

— Nate Christensen (@natech32)

September 9, 2024

I’ve seen this called the “sidecar motion.” The running back moves laterally in a path 5-6 yards behind the line of scrimmage to the sideline.

Last season, the San Francisco 49ers used it with running back Christian McCaffrey as a different way to give him free releases against man coverage on option routes. On Thursday, Reid used it a few times with running back Isiah Pacheco.

This first one comes from under center. The Chiefs are in 13 personnel, which the Ravens match with their base defense. Pacheco runs the sidecar before the snap — and then runs a rail route up the sideline. I’m not sure what coverage Baltimore called, but no linebacker travels with Pacheco. Unfortunately, Pacheco can’t bring in the pass — which easily could have gone for a touchdown.

Here we see the Chiefs use the sidecar motion from the shotgun, where it helps set up a screen pass. Pacheco motions to the right. A Ravens linebacker follows the motion, clearing a defender from the box. This gives the blockers a numbers advantage as they set up the screen.

As we see here, the sidecar motion can also help Mahomes identify the coverage. When the linebacker travels with Pacheco, the Ravens announce they are in man coverage. Mahomes then knows he can take a seven-step drop from under center — something you don’t see very often in today’s NFL — giving him the time to find tight end Noah Gray on a deep crossing route.

When Mahomes is under center in 12 personnel — as we see here — teams in nickel personnel often walk a safety down into the box. Someone has to travel with the sidecar motion. If it’s a linebacker, it’s man coverage across the board; one of Kansas City’s receivers can easily win. If it’s a defensive back, that puts a linebacker on a tight end — a matchup the Chiefs love to see.

On Thursday, wideout Rashee Rice was often covered by a linebacker. This is a problem against any wide receiver — particularly one as explosive as Rice. The Chiefs often created these favorable looks by using empty formations.

When a team uses an empty formation — one where the quarterback is alone in the backfield — there are specific checks for coverages against it. Typically, defenses will play some version of man coverage or a soft zone against an empty set. The defense’s alignment can reveal what it is doing. If a linebacker walks out over the running back, it’s usually man coverage. If a cornerback is out over the back, it’s typically zone coverage.

Kansas City can put teams in a bind based on what they do with tight end Travis Kelce. On Thursday, Kelce was effectively a decoy in these spots. The Chiefs would put him in the No. 2 spot on the trips side — that is, as the middle receiver on the three-receiver side of the formation. This forces the defense to make a declaration about the coverage.

The defense has to decide what to do with its slot defender. If it matches them up against Rice on the weak side, a linebacker has to cover Kelce one-on-one — or they have to walk a safety down to play single-high coverage. But in this game, the Ravens wanted to tend toward two-high coverages to limit explosive passes. So typically, this meant a slot defender was matched up against Kelce.

On the back side, this created an opportunity for Rice to attack a linebacker one-on-one in underneath zone coverage — and he’s just too quick and agile for the linebacker to have a chance.

On this play, the linebacker still makes an incredible play on the ball — but the alignments are similar. Kelce isn’t on the field for this play. But by putting the slot to the strong side — the way all defenses align — and playing two safeties deep, the defense still opens the favorable matchup.

Eventually, the Ravens adjusted to empty formations by walking a safety down and playing single-high. But the Chiefs can still build counters to that approach. When Hollywood Brown and Xavier Worthy are both available, the Chiefs will be able get their downfield game going against single-high coverages.

The speed of those two receivers (and Kelce and Rice having the versatility to win from different alignments) will force defenses to make concessions; they simply won’t be able to provide ideal coverage against all four. A quarterback like Mahomes — who can read the way defenses align to empty formations — can easily make the right decisions.