Mike Zimmer wanted answers to what's ailing the Vikings offense this week, so he assigned assistant coaches to what he described as typical bye-week duties of identifying their own tendencies and ways to adjust ahead of Sunday's game against the Panthers.

But there's something unquantifiable that only more time wearing the play-calling headset can teach first-year coordinator Klint Kubiak.

"The flow of the game," Kubiak said. "Making sure you're always having the next call ready, and not getting too dialed into what's going on on the field. Because you've got to be thinking a couple steps ahead there."

Game flow hasn't been kind to the Vikings offense. They've started on fire, scoring in four straight opening drives. But only the Jaguars, Dolphins, Bears and Texans have scored fewer points after halftime than the Vikings — including just two touchdowns, both in the season opener at Cincinnati. Fizzled fast starts beget a middling offense, ranked 11th in yards and 19th in points.

When the successful opening script runs out is when the 2-3 Vikings need more from players and the 34-year-old Kubiak. He and assistant coaches increased their focus this week on their own offensive film, looking for answers on top of crafting what they hope is another strong start against a fast Panthers defense.

"We've researched it an awful lot," Zimmer said. "We went through every possession in the second half. We've gone through down-and-distance tendencies, earned first downs, second down and long after a penalty, after a sack. I gave the coaches a lot of projects to do."

The additional research was done Monday, already a busy day as assistants such as running backs coach Kennedy Polamalu and receivers coach Keenan McCardell study the week's opponent, produce film cutups, and meet to pitch ideas for the week's game plan.

Polamalu, offensive line coach Phil Rauscher, and assistants Ben Steele and AC Patterson work on the run schemes; Kubiak, McCardell, quarterbacks coach Andrew Janocko and assistant Christian Jones focus on the passing game.

"We come together at some point and coach each other up on what we like," Kubiak said, "and what we're going to put on our call sheet that week."

Scripting a fast start

The opening script is formed throughout the week of practices. Coaches need to see how players handle certain plays, and how those designs unfurl against scouted defensive looks.

"We just get confidence in plays," Kubiak said. "Like hey, we got some good reps of this play, I like it versus the defensive looks we're seeing, and some point later in the week we put together our early calls."

The selected play calls are put into situational buckets on a play sheet that coaches handle on Sundays. The opening 10 to 15 plays, or "early calls," aren't aligned in order, but ranked by their favorites in a given scenario: first and second downs, third downs by distance — 2 to 4 yards or 12-plus — and areas of the field like the red zone or the opponent's 21- to 35-yard line.

They've led to fast starts, including three touchdowns and a field goal in the last four opening possessions. Kubiak credits his coaches for getting players confident in the plan.

"They go in their rooms and talk about each play, the strengths and weaknesses and what can go wrong," he said. "They just prepare them for everything so that early in the game nothing surprises them. Early in most games, the defense is giving you an unscouted look."

On Saturdays, players run through early calls in a walkthrough practice, like what quarterback Kirk Cousins' first play will be in a third-and-6 situation. Against the Lions, Cousins found Justin Jefferson on the opening third down for a 37-yard jump ball against single coverage.

It was Jefferson's only target beyond 15 yards downfield. After the big early play, Lions defensive coordinator Aaron Glenn often kept two safeties in deep coverage.

"Right after the first snap," Cousins said, "you really have to be ready to adapt."

'Stay fast, stay hot'

Kubiak couldn't find an answer on his play sheet after halftime of the 19-17 win against the Lions. The Vikings' fading offense left the door open for Detroit with four three-and-out series in the second half alone. Only the Jaguars are going three-and-out more frequently than the Vikings (31%) this season, according to Football Outsiders.

Both play calls and execution are to blame. There was little Kubiak could do about left tackle Rashod Hill getting tossed backward by Lions edge rusher Trey Flowers, who sacked Cousins on the first play of the third quarter. It was the worst-case scenario for a play designed with max protection to take a deep shot; seven blockers had to hold up for Adam Thielen and Jefferson running deep.

"It's up to us to execute after those [first] 15 plays," running back Dalvin Cook said. "It's not on them upstairs, it's on us to execute, and we're going to get better at that."

"That's something we're implementing this week," Cook added, "starting fast, stay fast, stay hot."

The following third-and-12 play left Kubiak wanting his call back. He chose a receiver screen to K.J. Osborn, but the Lions dropped eight defenders into coverage and swallowed it after 4 yards.

"Their defense did a good job there," Kubiak said, "and they had a better call than I did."

To fix second-half woes, coaches will implement another script, of sorts.

They get 12 minutes at halftime to talk through a plan with Cousins, who has been given more influence on offense and freedom at the line of scrimmage this season. But coaches have decided the plan out of halftime needs to be more concrete.

"I have to do a better job of giving us a defined plan going into the third quarter," Kubiak said. "I have to be more specific. Then we have to execute."

Part of the problem may be foundational. Under-center runs and play-action passes are pillars of the Kubiak scheme. Yet after two years among the league's elite, Cousins is averaging just 7.1 yards on play-action throws — 23rd among all quarterbacks, according to Pro Football Focus. That's down from 9.6 and 9.7 yards under Kevin Stefanski and Gary Kubiak.

Fullback C.J. Ham has also been a linchpin, but the Vikings haven't been the same with him on the field. Running and passing efficiency is down in the two-back offense, which, to Zimmer, has become too predictable this season.

"The good things are on film that we've done, and teams are going to put those on a card and practice them," Kubiak said. "That's just on me to keep evolving us and make ourselves unpredictable, but still do what we do best."