Death by a thousand cuts is the summary of this Vikings run defense, but the slashes became deeper by a Rams offense that, after Sunday's loss, is now the fourth to run for over 150 yards against coach Mike Zimmer's squad this season.

"They have a unique scheme, where they use the receiver, the extra guy that's over there, to kind of go [left or right] and our guys were jumping out at them instead of playing what they were supposed to play," Zimmer said. "So they ended up getting some big gashes in there."

Run or pass, the Vikings defense has fallen off under Zimmer as injuries, particularly at defensive end, and failed roster decisions and development, particularly at cornerback, continue to weigh them down. The past six weeks have marked a pronounced drop.

Since grounding the Chargers' Justin Herbert last month, the Vikings are allowing 393.8 yards and 25.6 points per game. Defenders kept those counting stats lower against the Rams — 356 yards and 23 points — but only barely against a jittery and off-target Matthew Stafford.

Meanwhile, Rams running back Sony Michel marched down the field unbothered at times while gaining 131 yards on 27 carries. The Vikings have two games against the Packers and Bears to prevent their current 4.7 yards allowed per carry from being the franchise's worst run defense since 2003.

"We know [run defense] is something we have to fix," cornerback Patrick Peterson said, "and knew that was something we had to slow down going into the game if we wanted to come out on top."

1. The Rams ran away with the game in the second half. After the Vikings settled for a field goal, pulling within 20-13, the Rams took the field having thrown three interceptions in the past five drives. Then they ran for 48 of 75 yards for an ensuing touchdown.

Sheldon Richardson, the veteran defensive tackle playing defensive end for the shorthanded Vikings, played 61 of 70 snaps on Sunday. That might've not been enough. The Rams immediately went at his replacement, third-round rookie Patrick Jones (#93), on the first play of this key drive.

Rams right tackle Rob Havenstein (#79) makes this 10-yard run by Michel happen with the extension of his right arm. Havenstein shoves Jones to the right, helping set up tight end Tyler Higbee for the block, and pivots to linebacker Eric Kendricks (#54). With Havenstein walling off Kendricks, and Higbee pinning Jones outside, there's an alley.

Nose tackle Michael Pierce (#58) is stalemated by Rams right guard Austin Corbett (#63). Nobody defeats a block for the Vikings defense, and it's 10 yards for Michel.

2. Rams coach Sean McVay also outfoxed the Vikings by setting up mismatches. The Vikings' worst days against the run this season have come against a few of the game's younger minds in the Browns' Kevin Stefanski, the 49ers' Kyle Shanahan and McVay. However, their worst was a 247-yard rushing day by the Ravens and veteran coordinator Greg Roman and quarterback Lamar Jackson.

Against the Rams, the Vikings defense was kept with five defensive backs in the huddle to match a three-receiver offense. Those lighter fronts struggled to hold up as slot cornerback Mackensie Alexander, playing through a rib injury, was brought into the fray. Zimmer countered at times with a three-safety nickel look, putting rookie Camryn Bynum deep and moving Harrison Smith into the slot, where he's closer to the action.

"They put guys in positions, our guys in positions that they're not necessarily comfortable playing," linebacker Anthony Barr said. "We'd have the nickel in the run fit a lot of times, and then sometimes we just missed a gap. We were not in our gaps, not in the right spots, so they just out-executed us in the run game."

On this second-and-7 play below, notice Richardson (left defensive end) is back in the game after Michel's 10-yard run just two plays earlier. This next run by Michel (#25) is set up through the aforementioned scheme. A three-receiver formation brings Alexander (#24) onto the field, and a condensed alignment keeps him in close.

Rams receiver Van Jefferson (#12) runs a jet sweep motion, which takes Kendricks (#54) and Barr (#55) out of position as they shuffle left toward Jefferson. Rams receiver Ben Skowronek (#18) pulls from right to left as the lead blocker.

Two more critical elements to this play: Rams left tackle AJ Jackson (#68), an undrafted rookie and injury replacement, knocks defensive tackle Dalvin Tomlinson (#94) sideways to widen the lane. Jackson can do this as a second blocker on Tomlinson, because Higbee (#89) and receiver Cooper Kupp (#10) double defensive end D.J. Wonnum (#98). After an initial push on Wonnum, Kupp slips behind Higbee and pulls as a second lead blocker.

The slick play design has two receivers lead blocking at Alexander. It's an 11-yard run.

"The things they probably do a little bit better than others is that Kupp will chip the defensive end like a tight end," Zimmer said. "He'll chip him and get up to the nickel, up to the linebacker. He's an outstanding player. Like I said during the week, he does a lot of dirty work. He's not just a receiver."

3. That drive ended with the 7-yard touchdown pass to Odell Beckham Jr., who beat Cameron Dantzler in a one-on-one situation. Dantzler has had some issues in the red zone this month, should you recall the Lions' game-winning touchdown on Dec. 5 followed by more blunders in the second half against the Steelers.

This time, the Rams appear to scheme Dantzler into a solo situation against Beckham. Kupp (#10) draws much of the Vikings' attention while aligned in a bunch formation in the open side of the field (ball on right hash mark). This is also the one play cornerback Harrison Hand replaced Alexander in the slot, as Alexander appeared shaken up briefly.

Dantzler (#27) keeps his outside leverage until Beckham fakes an inside move at the top of the route. Dantzler lurches inside, and Beckham cuts outside for the score. Stafford keeps his eyes to the left, working across the end zone and throwing right in about 3.2 seconds.