Case Keenum was on the type of streak that had him next to Tom Brady, at least through broadcast crews isolating his image and stats comparing their similar four-game runs.

His past month included: four of his top 11 career passer ratings (all above 100 now), 10 touchdowns to just two turnovers and nearly 1,100 passing yards with a 74-percent completion rate. The Vikings' skill position players had the fewest drops in football. The offensive line was opening holes and protecting just long enough.

Until Sunday's 31-24 loss in Carolina, where Keenum was sacked six times, had five passes dropped and committed three turnovers.

"Quite honestly, we didn't execute in a lot of areas," head coach Mike Zimmer said Monday. "Some guys played well, some guys didn't play well. Collectively as a group, we didn't execute well enough really on either side of the ball."

The Panthers' defensive front seven might be the best the Vikings face this regular season. Keenum still threw for 280 yards, but it didn't come easy while needing 55 dropbacks. He felt heat on nearly half of them against the blitz-happy Panthers.

"I keep hearing about, because I get these little things from [Vikings PR director] Bob [Hagan], 'he didn't throw the ball deep,'" Zimmer said. "Well, he got about a 50-yard touchdown with Adam. We try to take what the defense gives us. I thought he made some really, really good plays on a couple third downs. He made a couple bad throws."

Let's take a look at how Keenum and the Vikings' passing game sputtered, a key to Minnesota's loss in Carolina. Here to help is Dan Hatman, a former NFL scout and Director of Scouting Development at The Scouting Academy. You can follow Dan on Twitter @Dan_Hatman.

A balanced Vikings offense became unbalanced, which will happen when Minnesota's 8 first-down runs amassed 11 yards (total!). Dropping back to pass 55 times with just 16 handoffs is not the Vikings' blueprint followed during an eight-game winning streak. So don't let this passing breakdown let you overlook their need to get Latavius Murray, who had just 14 yards, going again.

Down 24-13 at the end of the third quarter, the Vikings handed it to Murray on first down. He was stuffed for a loss of three. An incompletion later, they're staring at third-and-13 when the Panthers blitz again. Carolina made the right call. With Vikings linemen prepping for a screen pass, and Jerick McKinnon forced to pick up pressure, heat quickly gets to Keenum. This counted as one of Keenum's six sacks. Kai Forbath missed the ensuing 54-yard field goal attempt.

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"Looks like a slow screen weak to the running back, but there is still a three-man route concept working the field," Hatman said. "Clearly, the pressure was called at a good time as the protection doesn't have the numbers. I want to be surprised Case escaped to his right [and not left], as there was no checkdown with the running back [McKinnon] engaged, but it's so heat of the moment."

The Panthers stymied the Vikings' effective play-action pass, as Keenum entered Week 14 trailing only L.A.'s Jared Goff in yards off play-action passes, according to Pro Football Focus. Whether it was Keenum's poorly-thrown deep ball on the first interception, or tight end Kyle Rudolph's drop down the seam, the Vikings were largely unable to create off one of their staples.

Only Marcus Mariota (in a Titans' 12-7 loss) had a worse passer rating off play action last week than Keenum, in part because of poor protection seen below. Yet this was one of the few examples that worked. On this second-and-3, Rudolph misses a blitzing Captain Munnerlyn and then needs to bail out Keenum, who ducks the pressure.

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"With the six-man protection, they should have been able to handle the slot blitz with the blockers," Hatman said. "It looks like Rudolph does not see [Munnerlyn] inching in, nor does he see him actually blitz off the edge. Keenum should not have to throw hot off that look."

When the protection was there, the throw or catch often was not. Evident when receiver Stefon Diggs got the one-on-one matchup with Munnerlyn on this third-and-2 below. As Hatman notes, right guard Joe Berger and center Nick Easton are solid handling the double A-gap blitz from Luke Kuechly and Thomas Davis.

Diggs gets a step on Munnerlyn, but Keenum's pass is underthrown allowing Munnerlyn to make the play on the ball. Keenum had two open receivers on this one. McKinnon slips from the backfield into a wheel route down the opposite sideline, which Hatman points out below.

The Vikings dropped five passes, one apiece from Rudolph, Thielen, McKinnon, Diggs and Laquon Treadwell.

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"The protection looked good here. Six up with the two linebackers sugaring inside, and they dealt with it well," Hatman said. "The slot fade from Diggs looked very good and the running back [McKinnon] against the zone-dropping defensive end may have been even better. Ball placement was an issue there, clearly."

Keenum's long ball was off in Carolina, with the highlights being his 18-yard touchdown pass to Rudolph and the 20-ish-yard pass to Adam Thielen, whose sprint capped a 52-yard touchdown. Behind a patchwork offensive line starting three backups by game's end, Keenum still showed that intestinal fortitude famously praised by Zimmer. He just missed the mark at times, which was the case on his first interception to end the opening drive.

On this second-and-14, the new center/left guard combo of Easton and Sirles surrenders the pressure in Keenum's face when he sees Thielen open downfield.

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"They did a half-line slide to the offense's left and Easton had help early on," Hatman said. "Easton never worked to position himself to sustain when or if the guard [Sirles] left, which caused the pressure. With the slide protection, he should have been able to wash him down around the pocket. I give Keenum credit for hanging in there versus pressure in his face, but that is a tough ball to throw. He's not known for having a phenomenal deep ball — like the slot fade earlier to Diggs."