How good is Northwestern?

College football polls show no mercy. On Oct. 4, Northwestern was No. 13 in the country, undefeated with quality wins against Stanford and Duke, and armed with one of the best defenses in college football. Fourteen days later, the Wildcats were confined to Big Ten mediocrity.

Following a crushing 40-10 loss at Ryan Field to Iowa, Northwestern then traveled to Memorial Stadium as 7-point underdogs. But against the odds, Northwestern avoided a fourth quarter collapse and held onto a narrow 30-28 victory that ensured its first bowl appearance since 2012. However, the question remains: How good is Northwestern, and how will they fare down the stretch?

The Wildcats definitely are not as bad as they were against Iowa and Michigan. It is hard to imagine any team looking as bad as Northwestern did in those two games, and after this week, the team has proven it can still play decent football. But, no, they are not the perceived defensive juggernaut that started the season undefeated and looked poised to contend for the Big Ten West. The team's quality likely lies somewhere between the two extremes of the season thus far.

The best place to start answering that question is with the defense, as it was the defining trait of that 5-0 start. After allowing 294 rushing yards and five rushing touchdowns to Iowa, Northwestern bounced back well against the run in Lincoln. The defensive line played magnificently, as Nebraska was limited to just 2.2 yards per carry. Defensive end Dean Lowry was all over the Nebraska offensive line, and in the Huskers' backfield all day. The only blemish was NU's failure to contain Armstrong near the goal line twice, which resulted in two scores. As long as Lowry and middle linebacker Anthony Walker can continue to lead the front seven, Northwestern's run defense should be just fine.

However, the win at Nebraska did not assuage concerns about the secondary, as the unit failed to demonstrate the consistency that it displayed during the first five games of the year. The secondary often seemed disorganized. Old Northwestern nemesis Jordan Westerkamp and speedy receiver Brandon Reilly were able to get wide open on multiple occasions. NU was actually bailed out by drops, and one very ill-advised Armstrong throw.

Northwestern will need to tighten up during the bye week if it wants to hold off NFL prospect Christian Hackenberg in two weeks. But despite some regression over the last three games, Northwestern remains 4th in the nation in passing defense efficiency.

Offensively, Northwestern came through when it mattered against Nebraska. Two long Clayton Thorson runs and a strike to Dan Vitale proved to be just enough. But it's hard to see the offense making huge strides. Although Thorson has shown flashes of his potential, the offense has been significantly below average, ranking 110th in S&P+ and 119th in total passing efficiency. The offense didn't necessarily regress against Michigan and Iowa; rather, it was always an issue, the difference being that earlier in the season, it's deficiencies were obscured by the defense's excellence.

If Northwestern's offense showed real signs of improvement Saturday, it's because Clayton Thorson showed real signs of improvement. With the offense in need of a spark, Northwestern's passing efficiency improved against Nebraska's leaky defense. Thorson averaged 6.3 yards per attempt Saturday — not great, but an improvement on his season mark of 5.5 YPA, which is 101st out of 107 qualified FBS quarterbacks this season. He also finally broke out as a runner for the first time since Week 1.

But how fluky was Thorson's performance? One one hand, he has looked more and more comfortable, even in the losses, and has begun to showcase his arm talent more regularly. But his game was also largely a product of three plays that aren't consistently replicable, or at least haven't been. It's impossible to expect Thorson to break off huge runs in the games to come, especially against better defenses like Wisconsin's and Penn State's.

The real point of concern has been Northwestern's running game, which has now been subpar for three straight weeks. Justin Jackson and co. were mostly held in check by Nebraska, with Jackson only managing 2.9 yards per carry. The offensive line didn't create much room for the running game, and has seemed to regress as the season has gone on. The line, and the rushing attack, must improve in order to supplement Northwestern's still-stagnant passing offense.

So, how good is Northwestern? Saturday brought signs of a return of the dominant defense that carried NU to 5-0. If the defense can be a top 15 unit in the country, rather than just an above-average one, the Wildcats might have borderline top-25 upside. And while the offense is still lousy despite a 30-point output, there is the occasional promising sign.

But Northwestern has fallen to 50th in S&P+ for a reason. The defense is no longer good enough to cover for the offense's mistakes, and the offense is still one of the worst in Power 5 college football.

Right now, Northwestern is not as good as the top teams in the Big Ten. It is not even close to the true top tier, and is likely a step behind Wisconsin as well. But the Wildcats can't be dismissed just yet as a possible 9- or 10-win team.