Big Ten power rankings: Week 7

Posted by ESPN.com's Adam Rittenberg

The top four spots remain unchanged after a week that featured no upsets in conference play. There's somewhat of a drop-off after No. 4, and there's not much separation between Nos. 5-8. No one should question the three teams at the bottom.

1. Ohio State (5-1, 3-0) -- The Buckeyes won a weird game against Wisconsin, proving that big plays can overcome very inconsistent offense. I don't see a more complete unit in the league than Ohio State's defense, and with the offenses struggling around the Big Ten, it's tough to see any team scoring many points against the Scarlet and Gray. Ohio State will need Terrelle Pryor to win a conference game or two at some point, but the Buckeyes remain the team to beat.

2. Iowa (6-0, 2-0) -- Some were surprised that Iowa didn't beat Michigan by more, but the Hawkeyes once again showed their resiliency by rallying from an early deficit and making big plays down the stretch. Defense and special teams have carried Iowa this season, and those units need to be sharp for upcoming road games against Wisconsin and Michigan State.

3. Penn State (5-1, 1-1) -- A pathetic nonconference slate is finally complete, and we'll finally learn more about Penn State in the coming weeks. Quarterback Daryll Clark has turned in back-to-back strong performances, and the defense is getting production from its standout players (Navorro Bowman, Jared Odrick). Penn State now must elevate its play another level against better competition.

4. Wisconsin (5-1, 2-1) -- Sure, the Badgers lost by 18 points at Ohio Stadium, but they showed why their 5-0 start wasn't a fluke. If Wisconsin can clean up the major mistakes, it should go on to a strong season. The Badgers need to get running back John Clay back on track, but they have to love what they're getting from senior defensive end O'Brien Schofield right now.

5. Minnesota (4-2, 2-1) -- With upcoming trips to both Penn State and Ohio State, Minnesota desperately needed to beat Purdue and the Gophers came through. Plus, they rediscovered their rushing attack thanks to Kevin Whaley and others. It's tough to see Minnesota winning these next two, but the Gophers still should be set up for a strong finish toward a bowl berth.

T-6. Michigan State (3-3, 2-1) -- The Spartans' defense delivered its second consecutive strong performance against Illinois, and the offense did some nice things before being hampered by injuries. Michigan State's margin for error remains slim after the slow start, and it needs to continue the momentum this week against Northwestern before Iowa visits Spartan Stadium.

T-6. Michigan (4-2, 1-2) -- Despite a 1-2 Big Ten mark, Michigan remains a dangerous team because of its talent level and ability to hang around in games. The Wolverines have some obvious flaws, including a lack of depth and way too many defensive breakdowns, but they should continue to make progress throughout the season. Head coach Rich Rodriguez needs to effectively manage quarterbacks Tate Forcier and Denard Robinson this week against Delaware State.

8. Northwestern (4-2, 1-1) -- The résumé still looks extremely weak for Northwestern, which has beaten three FBS teams that own a combined record of 1-16. It didn't help that the Wildcats struggled to put away a bad Miami (Ohio) team on Saturday. The defense appears to be coming around, but an offense without a consistent run game or many big-play threats needs to find a better rhythm Saturday against Michigan State.

9. Indiana (3-3, 0-2) -- What the heck happened to the Hoosiers in Charlottesville? Players and coaches undoubtedly are wondering the same thing after an embarrassing performance against Virginia. The 3-0 start seems like a distant memory, and Indiana must get back on track at home against Illinois this week. The Hoosiers' veteran-laden defense needs to bounce back fast.

10. Purdue (1-5, 0-2) -- The Boilers aren't really this bad, right? A team that outplayed Oregon on its home field and nearly knocked off Notre Dame? Well, the beauty of football is you tend to get what you deserve, and Purdue deserves a five-game losing streak after committing 20 turnovers this season. Major mistakes are cropping up in every game, and Danny Hope needs to get things fixed fast. Things don't get any easier with No. 7 Ohio State visiting Ross-Ade Stadium on Saturday.

11. Illinois (1-4, 0-3) -- There's clearly a preparation problem for Illinois, which has yet to score a first-half touchdown against a BCS opponent. Quarterback Juice Williams clearly isn't the problem with the offense, which continues to waste talent at wide receiver. It's simply stating the obvious, but Illinois must beat Indiana on Saturday to have any chance of salvaging the season.