Before Sunday's 33-27 loss to the Bears, Vikings coach Mike Zimmer said his staff's preparation included looking through every snap their teams had taken against quarterback Mitchell Trubisky.

But Bears coach Matt Nagy arrived at U.S. Bank Stadium with a plan to attack through running back David Montgomery, building Trubisky's throwing lanes with more play-action bootlegs than the Vikings have ever seen from him in their seventh meeting.

It wasn't the Nagy offense the Vikings are accustom to seeing as Chicago pivoted in a fashion not dissimilar to Minnesota's offense, taking advantage of overeager run defenses with throws on the run.

And the Vikings' run defense — missing four of its front seven — was overeager with the patchwork of linebackers and defensive linemen gashed for a season-worst 199 rushing yards. Trubisky added 144 of his 202 passing yards after fake handoffs.

Early play-action gains turned the Vikings' attention to bootlegs, widening the defense and softening the run support.

"Early on, they had some success with the boots and play-action game, kind of getting out on the edge," safety Anthony Harris said. "Once that kind of happened, it allowed them to kind of get the running game going inside a little bit and try to stay balanced."

1. It was a tough day to be a Vikings linebacker, the position caught in the middle of the Bears' shell game with the football. You can see Eric Kendricks' years of experience and savvy in how he fluidly transitions from run to pass support when recognizing an offense's play-action. That transition is not so smooth, understandably, with rookie linebacker Troy Dye, who replaced Kendricks (calf) for the third straight game. The Vikings would also lose Dye to a concussion by the third quarter.

Chicago also deployed a lot of pre-snap motion that can alter a defender's run gap, sowing potential confusion in a young defense. On the opening Bears touchdown, Harris (#41) appears to be clearing up any such confusion with Dye (#45) after Bears tight end Jimmy Graham motioned from the offense's right to left. Dye is locked in.

Too locked in, maybe. Dye (#45) overcommits to the backside running lane — moving three yards forward and to the offense's right — before recognizing Bears receiver Darnell Mooney (#11) 'leaking' across the formation and into the flat. Play-action 'leaks' are especially dangerous when they're speedy receivers like Mooney, and not tight ends.

Linebacker Eric Wilson (#50) attacks the passer on the bootleg, but Trubisky gets the pass over him for the 8-yard touchdown.

Could Wilson have helped? Absolutely. Seeing him cruise past Mooney to attack Trubisky made me think of this play from the 2018 Super Bowl between the Rams and Patriots. Much smarter football minds could tell you the million differences between the Vikings' situation and this one, but it is a similar Rams play-action bootleg with a "leak" under the formation by Rams receiver Josh Reynolds (#83).

Watch in the video below as Patriots linebacker Kyle Van Noy (#53) anticipates the play-action. Instead of attacking the QB immediately, he levels Reynolds to remove a target for Rams quarterback Jared Goff.

Now, Trubisky is a lot more mobile than Goff, so that affects strategy as far as the Vikings pinning down threats on Sunday. But Wilson could've leveled Mooney as Van Noy did to Reynolds, and maybe the result is different.

Highest single-game play-action rate (via PFF)
2020: 65.4%, Bears QB Mitchell Trubisky at Minnesota
2019: 64%, Rams QB Jared Goff at San Francisco
2018: 63.6%, Giants QB Eli Manning vs. Tampa Bay

2. Vikings defenders started to key on play-action bootlegs after the first quarter, which is when Montgomery really got going. On this first down below, defensive end Ifeadi Odenigbo (#95) abandons the backside run support to cut off Trubisky's bootleg. Linebacker Hardy Nickerson Jr. (#47) — replacing an injured Davis for a snap on this play — also widens to the right to defend the possible pass.

That movement helps widen the Vikings defense for Montgomery, who picks up nine yards on this run and could've potentially had more if he doesn't try to cut this back inside.

Most rushing yards vs. Vikings defense under Mike Zimmer
230 — at San Francisco, Week 1, 2015
218 — at Seattle, Week 13, 2019
216 — at Carolina, Week 14, 2017
214 — at Seattle, Week 14, 2018
199 — vs. Chicago, Week 15, 2020*

*Most by a Vikings' opponent in Minnesota since 2003
(or since 2010 'home' game vs. Giants in Detroit)

3. Without Kendricks, Anthony Barr, Danielle Hunter or Michael Pierce, the Vikings defense lacks the talent inside to spread apart on first downs and consistently stop the run. Defensive tackle Jaleel Johnson (#94) was among the many Vikings defenders with a rough day against the Bears offensive line.

And he was getting little help behind him on plays like this 14-yard Montgomery touchdown run on first down. Johnson and Nickerson Jr. (#47), this time replacing a concussed Dye as the middle linebacker, provide Montgomery little resistance here.

As Johnson (#94) approaches the quick double team from Bears left guard Cody Whitehair (#65) and center Sam Mustipher (#67), he's struck immediately under his right arm by Whitehair — the start of a pancake block that drives Johnson backward.

Mustipher (#67) has an easy time pivoting to Nickerson (#47), who overran his gap and is walled off before Montgomery cruises up Johnson's lane for a touchdown.

4. Trubisky even left meat on the bone against this Vikings secondary, but some savvy plays by the remaining veterans helped bait him into an occasional bad throw.

On this third down, the Vikings show pressure with six on the line of scrimmage. Safety Harrison Smith (#22) lurks nearby, selling a single-deep safety in Harris. Trubisky wants to attack the middle of the field via a couple routes by tight end Cole Kmet (#85) and receiver Javon Wims (#83).

Before the snap, the Vikings give him the look to do it. This is critical because, for some reason, Mooney (#11) is left wide open on a quick route to the first-down marker. And Trubisky misses him while locked onto the middle of the field.

Both routes are taken away as Smith (#22) and Wilson (#50) bail into coverage and take away lanes to Kmet (#85) and Wims (#83). Smith initially looks to help cornerback Cameron Dantzler, who is alone at the bottom of the frame on receiver Allen Robinson, before quickly pivoting to Kmet's route.