COLUMBUS, Ohio (AP) — Ryan Day will face old friend and mentor Chip Kelly on Saturday when 21st-ranked Ohio State hosts Northwestern.

Considering the struggles of Ohio State's defense, this might be the worst time for the Buckeyes to take on the Wildcats and their former offensive coordinator.

Kelly joined the Buckeyes' staff in 2024 as offensive coordinator after he resigned as UCLA's head coach. After Ohio State won the College Football Playoff title, Kelly left to join the Las Vegas Raiders staff as offensive coordinator before being fired in late November after a 2-9 start.

Day had an opening on his staff after the season when Brian Hartline left to become USF's coach, but Northwestern beat Ohio State to Kelly and hired him in late December.

Day on Tuesday did not delve much into how serious talks got about Kelly returning to Ohio State. The relationship between the two goes back nearly 30 years, when Kelly was the offensive coordinator at New Hampshire and Day was his quarterback.

After graduating, Day joined New Hampshire's staff as tight ends coach and was an assistant under Kelly in the NFL with Philadelphia and San Francisco before coming to Ohio State in 2017 and being named head coach two years later.

“He’s been a friend, a mentor, an uncle, a brother to me his whole life. I’ve never coached against him, so this will be a first, but we’re always talking and always having conversations," Day said.

Northwestern coach David Braun said earlier in the week that there are usually some interesting and interconnected relationships between coaching staffs going into games, but admitted the one between Day and Kelly might be a little deeper.

“Is there some information that Chip may have just in terms of how they’re structured because of his time there? Absolutely. Those are things that you just need to be aware of and it’s making sure you don’t go down the rabbit hole of overthinking that either,” he said. “You've got to study what they’ve put on tape, who they are this year, and be objective in your approach.”

The relationship will run even deeper beginning next year when Day's son, RJ, arrives at Northwestern after graduating from Columbus DeSales High School. RJ Day committed to the Wildcats last year, a couple months after Kelly was hired.

Ryan Day's focus though is making sure he stops Northwestern's current quarterback, Aiden Chiles. The junior leads the Big Ten with a 68.8% completion rate and has accounted for 23 touchdowns (13 passing, 10 rushing).

If Ohio State is going to bounce back after losing consecutive regular season games for the first time since 2011, the defense will need to get back on track. Matt Patricia's unit allowed a combined 21 explosive plays in losses to Southern California and Oregon. Thirteen of those came in the 41-28 Oregon loss — four runs of at least 10 yards and nine passes gaining at least 15 yards.

Six of the explosives allowed the past two games have been on either third-and-long or fourth down.

“It just changes everything from the rhythm of the game and the outlook and then maybe some of the next calls that come after that and some of the things that you’re doing schematically," Patricia said. "We've got to do a really good job of just trying to eliminate those and making sure that we’re very clear with the assignments and the jobs and making sure that I simplify enough for those guys so they can still play fast and aggressive in those situations and making sure that we’re playing for the full part of the game.”

Both teams come into the game 6-3 and on two-game losing streaks. The Buckeyes have slim hopes of making the Big Ten title game at 4-2 while the Wildcats are 3-3 in conference play.

Ohio State is looking to avoid its first three-game losing streak since 2011 while Northwestern is trying to win at Ohio Stadium for the first time since 1971, a span of 15 games. It is the Wildcats first time to The Horseshoe in 10 years.

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