Gophers coach Jerry Kill and offensive coordinator Matt Limegrover have worked together since 1999, back when freshman quarterback Demry Croft was 2 years old and college teams averaged 25.6 points per game.

Kill and Limegrover molded offenses that consistently improved at each of their stops together — until this year. The Gophers rank second-to-last among the 128 Football Bowl Subdivision teams in scoring, at 15.4 points per game.

That’s about half of this year’s national average (30.4).

At a time of scoreboard-busting offense, the Gophers enter Saturday at a pivotal juncture. They’ll face the Big Ten’s worst defense at Purdue, with a chance to either change their disappointing narrative or amplify their critics.

They’ll be in West Lafayette, Ind., where they haven’t won since 2008, with the Boilermakers coming off a confidence-building three-point loss to No. 4 Michigan State.

The Gophers will be without eight injured starters, Kill said, including two offensive linemen. True freshman Tyler Moore, the team’s backup center, tweeted that he’ll be making his first college start.

Limegrover wears two hats, as offensive coordinator and offensive line coach. Each one is burning hot, with the fire raging beneath.

“This has been the biggest challenge of my career,” Limegrover said. “Usually, when the O-line isn’t going well, the whole thing isn’t going well. That’s just how it works.”

Limegrover isn’t the only Big Ten offensive coordinator with this dual role. Ohio State’s Ed Warinner, Michigan’s Tim Drevno and Wisconsin’s Joe Rudolph are among other coordinators who also coach the offensive line.

“That’s not an easy gig,” Kill said.

Especially now. A 10-7 win over Kent State raised red flags three weeks ago, especially since Illinois had crushed that same opponent 52-3. Last week, the Gophers suffered their first shutout loss to Northwestern since 1959.

Kill replaced junior quarterback Mitch Leidner in the fourth quarter, pulling a potential redshirt from Croft. Leidner will start at Purdue, Kill said, but it will be interesting to see how the Gophers use Croft, moving forward.

Kill said he and Limegrover were up past midnight dissecting the offense last Sunday, and that was just their first day of preparation for Purdue.

“Coach Kill’s been great,” Limegrover said. “He’s been involved [with the offense]. He’s trying to do his best to take some of that off me from the bigger picture, so I can focus on getting that O-line squared away. Because it’s amazing, once that gets worked out, then the other things will start to come again.”

According to their depth chart, the Gophers will have starting left tackle Ben Lauer back from injury. Jonah Pirsig is moving to right tackle, with Josh Campion a backup at both tackle spots.

Jon Christenson also is due back from his knee surgery, and the plan is to have him split snaps at left guard with Joe Bjorklund.

Kill makes no secret that he wants to re-establish the running game, behind freshmen tailbacks Rodney Smith and Shannon Brooks. The Boilermakers rank 99th in the nation in rushing defense (193 yards per game), but much hinges on Minnesota’s offensive line.

“[Limegrover] really stresses being consistent,” Pirsig said. “That’s when we click as an offensive line, that’s when we’re having fun. When we get tight, we’re kind of worried. We’re kind of playing like robots, and that’s when the mistakes happen.”

A faster start would help. The Gophers have scored just three first-quarter points, combined, in five games. Limegrover said he scripts the game-opening plays, but the sequences just haven’t worked.

“It’s been a struggle; it’s hard,” Limegrover said. “We’re trying to find different ways before that ball is even kicked off to try to get those guys going a little bit because it’s like there’s a tentativeness to it.”

Added senior receiver KJ Maye: “I just feel like we come out a little lazy, not ready to go.”

Kill sensed it last week, for sure. He told the players it looked like “Northwestern wanted it more,” adding that it reminded him of last year’s loss at Illinois.

“[The Wildcats] hit us in the mouth,” Kill said. “They play physical. They’re really good on defense and don’t turn the ball over. They beat us at our game.”

Kill said he didn’t let a single mistake slip this week at practice. If a player missed an assignment, the whole team did “up-downs,” where everyone runs in place and then hits the ground at the coach’s whistle.

Before leaving for Purdue, Kill told the players: “You better be motivated, or we’ll be the first team doing up-downs on national TV. Don’t think I won’t do it.”