Zach Harrison and the defensive line’s preparation did not change as Ohio State shifted its focus to Purdue.

No matter what type of offense the Buckeyes face, it’s getting the game plan Tuesday and working to make it as perfect as possible until kickoff Saturday.

Setting up the game plan remained the same too: going off what the coaches saw from film and trying to put the defense in the best position to be successful, utilizing the fundamentals of pad level, defeating blocks and rallying to the football.

“At this point in the year, I think we have a pretty good handle on who we are,” Ohio State head coach Ryan Day said. “Now it’s just a matter of executing and playing well.”

Ohio State’s game plan against the Boilermakers was a different look than it was used to.

Facing primarily a pass-heavy offense for the first time all year, Day and the coaching staff decided to utilize a defense that used a three-man front, dropping eight back into coverage instead of the four-man front Ohio State was used to.

Even when Ohio State mixed in those traditional four-man fronts on the line, a defensive lineman found himself dropping back, using him as the extra cover man.

With that, the Buckeyes failed to bring any pressure in the pass game, generating no quarterback hurries or sacks, while each of the defense’s five tackles for loss game in the ground game or when the ball was already thrown.

Responding to the lack of pressure, Purdue quarterback Aidan O’Connell completed 76.9% of his passes for 390 yards and four touchdowns.

“I think it gives you a different look. The windows change, but you still have to execute your defense,” Day said of Ohio State’s three-man defensive front. “I don’t think we did that well enough to be quite honest.

“Obviously there’s give and take with everything, right? When you rush three, you buy an extra guy in coverage, but also lose a bit of the pass rush. We make a decision based on what gives us the best chance that week is what we’ll do.”

For Harrison, O’Connell’s quickness was a challenge for the line, saying that the quarterback was “pretty much catching and throwing the whole game,” but that his unit failed to take advantage of the opportunities it had when the quarterback held the ball a bit longer.

Day said Ohio State doubled-down on the pass-first defensive look especially when the score became lopsided early.

“Certainly, there were times where we could tighten up the coverage and other times where we probably could have gotten to the quarterback faster,” Day said. “There’s a lot of things on that film that we learned, especially facing a more pass-heavy team.”

Prior to Saturday’s game against Purdue, Ohio State had 34 sacks in its first nine games, tied with Marshall and Troy for the most in the country. As the Buckeyes prepare for Michigan State, they have fallen all the way to sixth, passed up by Oklahoma State, Pittsburgh and Ole Miss.

When Ohio State has gotten to the quarterback faster, it’s found much more success.

The Buckeyes have four games this season in which it has recorded at least five sacks and at least eight tackles for loss: Nebraska, Indiana, Maryland and Akron. In those games, the defense has allowed an average of 249.3 yards per game and no more than two offensive touchdowns.

In every other game this year, Ohio State has allowed 439.2 yards per game with four games in which the Buckeyes defense allowed three touchdowns or more.

“The d-line is a key part to stopping the passing game,” Harrison said. “If the quarterback is there with all the time in the world, he’s going to pick any defense apart. It’s on us to get him uncomfortable, get him off the spot and get him on the ground.”

Day knows that each week is different.

This week’s focus is on Michigan State: an offense that has allowed 16 sacks in 10 games, which is the fourth least in the Big Ten; an offense that is much more balanced than Purdue’s with Kenneth Walker III at running back and Payton Thorne leading a pass offense that has the fourth-best completion percentage in the conference, along with being one of four teams with at least 20 passing touchdowns.

Ohio State’s defense is probably not going to drop back eight into coverage against Michigan State like it did against Purdue. But the goal will be the same as when it did drop eight.

To Day, it doesn’t matter how many Buckeyes are rushing the line of scrimmage. Ohio State’s defense still has to execute. But he knows the defensive line, the pass rush us a huge part of that success.

“It’s everything,” Day said. “Tying up the front with the back end is exactly how you put a defense together.”