COLUMBUS, Ohio — Halfway through the season, Ryan Day says he still is learning about his No. 3 Ohio State Buckeyes.

The fifth-year coach should know a lot more Saturday when the undefeated Buckeyes (6-0, 3-0 Big Ten) get a visit from undefeated No. 7 Penn State (6-0, 3-0). The game will help define the rest of the season for the Big Ten East rivals and possibly bring the College Football Playoff picture into focus.

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That the Buckeyes’ identity isn’t fully formed yet is “probably something you can say about a lot of teams across the country,” Day said this week.

“I don’t know if I have a good feel for who we are as a team,” he said. “But now it’s time to go play again in a matchup game again. We’ve certainly learned a little bit about the quarterback. We’ve learned a little bit about some of the guys who we didn’t know early in the season.

“But we have the pen to go write the script of what the season is going to look like, and that’s really what matters.”

Penn State will try to end a six-game skid against the Buckeyes and gain an upper hand in the Big Ten East and the College Football Playoff. No. 2 Michigan still lies ahead for both teams.

Statistically, the Nittany Lions have the best defense in the land. The Buckeyes defense also is ranked in the top 10. Penn State’s only win against a ranked team came in Week 4 when it routed then-No. 24 Iowa 31-0. The Buckeyes’ signature win was a 17-14 thriller over then-No. 9 Notre Dame on Sept. 23.

Both teams have first-time starting quarterbacks in Penn State’s Drew Allar and Ohio State’s Kyle McCord, who are getting more comfortable in the job every week.

“It’s just that when you’re in games like this, as we know, it could come down to one play, so everything is amped up,” Day said. “The consequences are higher, the stakes are higher, and that’s the way you want it.”

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Ohio State has won the last six games in the series after a 24-21 Penn State win in 2016 helped propel the Nittany Lions to their only Big Ten championship under coach James Franklin. That was their first win in the series with Ohio State since 2011, which was also the last time they won in Columbus.

Some of them have been heartbreakers for Penn State.

The Buckeyes overcame fourth-quarter deficits to win by a single point in 2017 and 2018 and came from behind again to win in 2021.

Last year, Ohio State defensive end J.T. Tuimoloau had a day most defensive players can only dream about. Tuimoloau intercepted Sean Clifford twice, one a pick-six. He also had two sacks, caused and recovered a fumble and tipped a pass for another takeaway. The Buckeyes won 44-31 in State College. Pa.

“We’ve played these guys for a long time,” Franklin said. “Probably up to the last two years, probably played them as well as anybody in the conference. But we got to find a way to be able to win in the fourth quarter and win these one-possession games.”

Ohio State backs are battling injuries for the second straight season. TreVeyon Henderson and Miyan Williams were held out of last week’s game because of unspecified injuries, and Chip Trayanum had to leave the game after he got hurt. Second-year back Dallan Hayden — a player Day had hoped to redshirt — carried the load, getting the ball 11 times for 76 yards and a touchdown in the 41-7 win over the Boilermakers. Day said the three injured players might be back Saturday.

The Nittany Lions are at the top of national defensive rankings, limiting opponents to an average of 193.7 yards per game. They’re also No. 1 in pass defense (121.2), pass efficiency defense (80.73), completion percentage (49.1), first downs allowed (67), sacks per game (4.5) and red-zone attempts (7).