5 storylines: Penn State at Iowa

Every week, NittanyNation takes a look at five storylines that stand out: What should fans keep an eye on? What's the bigger picture? What might be on display Saturday?

Here are NittanyNation's Week 8 storylines:

1. Iowa running game: You might not hear panic in Kirk Ferentz's voice, but these Hawkeyes are in trouble. Without their top offensive weapon in Mark Weisman, who's listed as doubtful, the Hawkeyes are forced to resort to Plan C. Damon Bullock is still reeling from a concussion, so Saturday's load will fall on the inexperienced shoulders of true freshman Greg Garmon -- an unknown whose name was misspelled on Iowa's official depth chart. He's a wildcard, carrying the ball just 14 times this season and averaging just 2.5 yards a touch. Iowa's offense could be in for a long day.

2. Fourth-quarter comebacks: Quick, what team's had the most fourth-quarter comebacks since 2009? That would be the Hawkeyes. Iowa has marched to nine comebacks in the final quarter, meaning it rallies for a win about 20 percent of the time. And Penn State hasn't done terribly in this department either; it just celebrated an 11-point comeback over Northwestern, one that entailed scoring 22 fourth-quarter points. Both of these teams know how to rally, and neither team can be counted out Saturday. At any point.

3. Two strong defenses: Whenever Penn State was asked about Iowa's defense, one term kept popping up: Physical. Iowa could define the Lions' defense the same way. Just look at the numbers: Scoring defense: PSU No. 15, Iowa No. 21; total defense: PSU No. 32, Iowa No. 19. We could go on, but you get the idea. These two defenses love to hit, and they share a lot of other similar characteristics. Anyway you look at it, this matchup has the potential to be a low-scoring affair -- even if Matt McGloin disagreed Wednesday afternoon.

4. Bill Belton or Zach Zwinak: Bill Belton seemed slower than usual early on against Northwestern, and Bill O'Brien pulled him in favor of Zach Zwinak. Now that Belton had a bye week to heal, will his speed return? The sophomore tailback is listed as No. 1 on the depth chart, but these two could still split carries. Zwinak rushed for 315 yards in the last three games, but O'Brien seems enamored with Belton's ability for the big play -- something sorely needed in Penn State's offense. Something has to give here, but what will it be?

5. Field-goal units: In a game with two strong defenses, this matchup has the potential to fall on the placekickers -- and Iowa has the clear advantage. Mike Meyer has twice earned Lou Groza Star of the Week honors by connecting on 14 of 15 field goals this season. He's made 13 in a row and, unless that number somehow jinxes the Hawkeyes, Penn State could be in a lot of trouble. Meyer is automatic under 40 yards, and he has the leg to hit 50-yarders. Penn State? Well, every fan is aware of Sam Ficken by now. The sophomore kicker boasts one of the worst accuracy rates in all of college football, and he doesn't have an "automatic" range. If Penn State can't find the end zone against a tough Iowa defense, the game could fall to Ficken.