DETROIT – Case Keenum is becoming Gluten-Free Favre: He provides all of the offensive nourishment of the original, with turnovers reduced for your digestive health.

With another tasty-yet-nutritious performance on Thursday, Keenum engineered the Vikings' most important divisional victory of the season, a 30-23 decision over the Detroit Lions at Ford Field that turned the two most intriguing questions of the season into afterthoughts.

Can the Vikings win the NFC North? They just did.

Will Keenum hold on to the starting job? He'd have to mimic a man falling down a staircase with a box of scissors to lose it now.

"Yeah,'' Vikings coach Mike Zimmer said. "It's simplified.''

Zimmer was the one who raised the possibility of Teddy Bridgewater playing this season, after Keenum threw two unsightly interceptions against Washington. Now that Keenum has led the Vikings to seven straight victories Zimmer can't play games with his most important position, not even to appease Bridgewater.

The Vikings are 9-2 and competing for one of the top seeds in the NFC, and since those two interceptions in Washington, Keenum has played as well as any quarterback in the league. Thursday, he completed 21 of 30 passes for 282 yards and two touchdowns, and ran seven times for 20 yards and a touchdown.

He also moved like a breakdancer in the pocket, avoiding most rushers and standing in the pocket and taking hits when there was a big play to be made.

That's what happened in the second quarter. Lions safety Miles Killebrew blitzed and did not see a Vikings jersey until he was smashing Keenum to the turf. Keenum's pass was already gone, landing perfectly in tight end Kyle Rudolph's hands in the end zone for a 22-yard touchdown.

Keenum has thrown 14 touchdowns and five interceptions this season. In the past three weeks he's beaten Kirk Cousins, Jared Goff and Matthew Stafford, who makes $25 million a year more than Keenum. Keenum's ability to outplay Stafford is the key factor in the post-Aaron-Rodgers-injury portion of the season.

If the Vikings were planning to turn to Bridgewater, either as a strategic move or a tryout, starting him in Atlanta after a 10-day break would have made sense. Keenum has taken that move off the table the past two weeks.

Now that it's obvious to everyone that Keenum has to remain the starter until or unless something strange or disastrous happens, the ghosts of Vikings quarterbacks past become Keenum's most worrisome opponents.

Only one quarterback in Vikings history — Fran Tarkenton — has defined himself as an enduring and elevating franchise quarterback. Everyone else has teased, crashed, or wrongly been discarded.

Joe Kapp. Tommy Kramer. Wade Wilson. Sean Salisbury, who was wrongly chosen to replace Rich Gannon in 1992, leading to a decade of free-agent quarterback imports.

Brad Johnson won a Super Bowl … with the Bucs. Randall Cunningham led the Vikings to an NFC Championship Game, then got himself benched early the next season. Daunte Culpepper produced a near-historic season in 2004, and was gone two years later. Tarvaris Jackson and Christian Ponder started in playoff games while proving themselves dispensable. Brett Favre performed for one year like he had sold his soul for a championship, then played the next as if the bill had come due.

To believe in Keenum is to embrace the moment and blind yourself to history. Which might be the way to go. For all of the money and time NFL teams spend on planning and evaluation, at some point shrugs win the day. Keenum's playing great? Cool. Roll with it.

That seems to be Keenum's motto. At 29, he's playing better than he ever has before, and doesn't seem surprised. "I'm ultra-competitive,'' he said. "I want to be great.''

I asked Keenum whether he has improved, or whether his improvement is due to circumstance — playing for a better team at just the right time. In the mode of most modern NFL players, he talked for a while without coming close to an answer.

Maybe because it doesn't matter. Keenum is playing like a star, whether he is one or not.

Jim Souhan's podcast can be heard at MNSPN.com. On Twitter: @SouhanStrib. • jsouhan@startribune.com