When last seen at Memorial Stadium, Nebraska had just dominated Purdue in the second half, improving to 7-0. Mike Riley’s team had flaws, but it debuted at No. 10 in the first College Football Playoff rankings.

Now, some of the old doubts have resurfaced in Lincoln, as the Cornhuskers return home Saturday to face the Gophers. After an overtime loss at Wisconsin, the Cornhuskers looked helpless in last week’s 62-3 loss at Ohio State.

Quarterback Tommy Armstrong Jr. was knocked unconscious when his head hit the turf, though all signs Thursday pointed to the senior returning for the Gophers game. Armstrong makes that team go, but even with him, the Cornhuskers are vulnerable.

“Everybody here realizes our struggles have not just been in the Ohio State game but before that, too,” Riley said. “So we’ve really got some work to do.”

Nebraska and Minnesota are both 7-2 overall and 4-2 in the Big Ten, making this the biggest game yet for the Gophers.

It’s also daunting, with the kickoff slated for 6:30 p.m. Nebraska has won 18 consecutive prime-time home games, with the last such loss coming in 2008. The Gophers silenced the Sea of Red at Memorial Stadium two years ago, but that game started at 11 a.m.

“They’ll be hungry, itching to get back out on the field,” Gophers quarterback Mitch Leidner said. “So we’ll definitely have to be ready to go. You can’t compare scores or anything like that. We’ve learned that a couple times this year.”

The Gophers have won four straight to keep alive their dream of winning the Big Ten West. It’s similar to the wave Nebraska was riding three weeks ago, having reeled off wins against lesser competition.

Nebraska peaked in September, when it combined to rush for 538 yards in back-to-back wins over Oregon and Northwestern. Armstrong didn’t throw an interception in either game and made several big plays with his arm and feet.

But the Huskers’ rushing struggles hit in mid-October. They are 8-0 over the past two years under Riley when rushing for 200 yards, but they managed just 152 at Indiana and 157 against Purdue.

“It’s a fallacy to look at that 7-0 record and say everything was perfect, when it was not,” Riley said. “We played our best ball late in games. But some of these things that showed up way too often [at Ohio State] were there.”

Armstrong threw two interceptions and completed just 38.7 percent of his passes at Wisconsin, but the Badgers do that to a lot of quarterbacks. In a hostile environment, Riley’s squad showed resilience that night, outscoring Wisconsin 10-0 in the fourth quarter.

For the season, Nebraska has outscored teams 108-20 in the fourth quarter. But the first three quarters were so bad last week in Columbus, none of that mattered.

Nebraska had used the same five starting offensive linemen for seven of nine games, but right tackle David Knevel and right guard Tanner Farmer missed the Ohio State game because of injuries. The Huskers wound up rushing for just 78 yards.

The offensive line is closer to full strength this week, but Riley cited concerns about the mounting linebacker injuries: Marcus Newby (hamstring), Dedrick Young (ankle), Michael Rose-Ivey (elbow) and Chris Weber (knee).

“I’m not sure that any of them can’t play, but they could be listed as questionable,” Riley said.

When healthy, Nebraska’s defense has been tough. Before the Ohio State game, the Huskers ranked 15th nationally in scoring defense, allowing 18.1 points per game.

But a lot of things looked better for Nebraska before that game.

BIG TEN SHORT TAKES

• As the Detroit Free Press noted, eight quarterbacks have left games early vs. Michigan this season. It’s either been injury (Maryland’s Perry Hills, Colorado’s Sefo Liufau, etc.) or ineffectiveness (Rutgers’ Chris Laviano, Michigan State’s Tyler O’Connor, etc.). “It’s a violent game. Nobody makes it out alive,” defensive end Chase Winovich said. “Nobody’s safe in this game, especially if you’re playing quarterback against us. We’re coming.”

• Iowa’s C.J. Beathard is next for Michigan. The Hawkeyes have been a disappointment, but don’t blame Beathard. His pass protection stinks. Iowa’s one receiver who could stretch the field (Tevaun Smith) graduated, and possession receiver Matt VandeBerg was lost to a season-ending foot injury. Beathard still has a 59.9 completion percentage, 13 touchdowns, five interceptions and a 133.0 passer rating.

• Northwestern plays at Purdue before coming to TCF Bank Stadium next week. That still looks like it will be a tough test for the Gophers. The Wildcats beat Michigan State, Iowa and Indiana before losing 24-20 at Ohio State and 21-7 at home to Wisconsin. Northwestern has had some of the Big Ten’s top performers in conference play with QB Clayton Thorson, RB Justin Jackson and WR Austin Carr.

BIG TEN POWER RANKINGS

1. Michigan (9-0, 6-0): Jim Harbaugh thanked D.J. Durkin for the memories, and then rubbed Maryland’s nose in it.

2. Ohio State (8-1, 5-1)

Jashon Cornell, redshirt freshman from Cretin-Derham Hall, has three tackles in three games.

3. Wisconsin (7-2, 4-2): Corey Clement has averaged 121.5 yards over the past four games, punching his NFL ticket.

4. Penn State (7-2, 4-2): Eyeing a New Year’s Six bowl, Penn State finishes with Indiana, Rutgers and Michigan State.

5. Nebraska (7-2, 4-2): Huskers’ average time of possession: 32:44. Minnesota’s average time of possession: 32:01.

6. Gophers (7-2, 4-2): Team has six TD passes. Only two FBS teams have fewer: Wake Forest and Vanderbilt.

7. Northwestern (4-5, 3-3): The Wildcats have wins at Michigan State and Iowa but are 2-4 at home.

8. Iowa (5-4, 3-3): Hawkeyes had won nine road games in a row before last week’s 27-point loss at Penn State.

9. Indiana (5-4, 3-3): Hoosiers need one win vs. Penn State, Michigan or Purdue to go bowling like last year.

10. Maryland (5-4, 2-4): The Terrapins have given up 650-plus yards in back-to-back losses to Michigan and Indiana.

11. Illinois (3-6, 2-4): Illini head to Wisconsin after becoming the latest team to a break a slump vs. Michigan State.

12. Michigan State (2-7, 0-6): Rushing offense is the only bright spot for a team in a surreal seven-game tailspin.

13. Purdue (3-6, 1-5): Combined halftime scores against Nebraska, Penn State, Gophers: 59-50. Second half: 10-83.

14. Rutgers (2-7, 0-6): Six straight losses now.