Big Ten power rankings: Week 6

Posted by ESPN.com's Adam Rittenberg

Ohio State is the clear No. 1 in this league, and Wisconsin has moved into striking distance after its impressive 5-0 start. There's some shuffling in the middle, while the league's bottom two teams are pretty obvious.

1. Ohio State (4-1, 2-0) -- The Buckeyes lost a few style points down the stretch against Indiana, but their defense once again turned in a dominant performance. Quarterback Terrelle Pryor seems to be making steady progress, and Brandon Saine could be the answer at running back. Ohio State's defense will be tested by John Clay, Scott Tolzien and the streaking Badgers.

2. Iowa (5-0, 1-0) -- A letdown against Arkansas State wasn't a huge surprise, though Iowa actually started strong before a shaky second half. The next two weeks will tell a lot, as Iowa hosts Michigan before visiting Wisconsin. Iowa has a BCS bowl-worthy defense, but how much longer can the Hawkeyes survive major mistakes and inconsistency on offense?

3. Penn State (4-1, 1-1) -- The Lions inched a bit closer to the No. 2 spot with an impressive second-half performance against Illinois. Penn State proved it could run the ball with multiple ball-carriers, and the new-look offensive line overpowered the Illini down the stretch. The line has been the biggest question mark for Penn State, and Joe Paterno had to like what he saw on Saturday.

4. Wisconsin (5-0, 2-0) -- Clay and the Badgers are arguably the biggest surprise in the Big Ten this season. After struggling on the road last season, Wisconsin kept its poise and outlasted Minnesota. With a power run game, a capable quarterback and an extremely opportunistic defense, the Badgers are showing that they're for real this season.

5. Michigan (4-1, 1-1) -- After playing with fire twice in the first four weeks, Michigan finally got burned against Michigan State. Freshman quarterback Tate Forcier has been brilliant in the clutch, but the Wolverines clearly have some flaws on both sides of the ball. Things don't get any easier this week as Michigan travels to Iowa City for the first time since 2005. Iowa-Michigan games at Kinnick Stadium are usually close affairs.

6. Minnesota (3-2, 1-1) -- I still have my doubts about the teams below the Gophers, so they stay in the No. 6 hole despite a home loss to Wisconsin. Mistakes continue to haunt Tim Brewster's team, which got flagged for nine penalties and couldn't convert red-zone opportunities into touchdowns. Wideout Eric Decker is a stud, but Minnesota needs a little bit more to be a truly good team.

T-7. Michigan State (2-3, 1-1) -- The Spartans move up three spots after their emotion-charged, overtime win against archrival Michigan. They overcame their typical fourth-quarter collapse, and a veteran-laden defense finally performed to expectations, especially against the run. This team still has some flaws, but I liked the resiliency the Spartans displayed Saturday.

T-7. Northwestern (3-2, 1-1) -- Much like Michigan State, Northwestern had been waiting for a breakout performance from its experienced defense. The Wildcats got one against Purdue, which committed six giveaways in a 27-21 loss. Northwestern can't expect to win many more games like Saturday's, but the Wildcats defense clearly gained a lot of confidence. If the unit can build off of this win, Northwestern could make a nice run in October.

9. Indiana (3-2, 0-2) -- Not a horrendous performance by the Hoosiers against Ohio State, but they made too many mistakes to keep the game close on their home field. The final score could have been a lot uglier, but three turnovers plus a safety put the game out of reach in the third quarter. This week's trip to suddenly resurgent Virginia looms large in terms of whether Indiana makes a bowl push.

10. Purdue (1-4, 0-2) -- Cue the Red Hot Chili Peppers. Purdue's theme song this season has been "Give it away." To commit six turnovers on your home field is unacceptable, and it continued a trend where the Boilers lost a game that they controlled at some point. Head coach Danny Hope has some playmakers, but they just aren't finding ways to win games.

11. Illinois (1-3, 0-2) -- These are desperate times for Ron Zook, Juice Williams and the Illini, who are headed for their second consecutive losing season despite boasting loads of talent on offense. Illinois has been outscored 102-26 in three games against FBS foes. Zook is on the hot seat, and he has an interesting decision to make with Williams, his senior quarterback. This week's game against Michigan State is an absolute must win.