Ohio State is just days out from completing its 2021 season with an incredibly memorable win against Utah in the Rose Bowl.

After already taking a look at the Ohio State offense, let's take a deeper look at how the Buckeyes did on the defensive side of the ball.

Ohio State's numbers say it got to the quarterback in 2021.

The Buckeyes finished the season with 37 sacks through 12 games, good for 30th best in the country, tied with Air Force and Liberty, averaging 2.85 sacks per game. A lot of that came from the defensive line, as Larry Johnson's room recorded 31.5 (85.1%) of the team's total.

But for a roster that has seen three players record 10.5 sacks or more since the 2014 season, Ohio State never really had that dominant player up front, with senior defensive tackle Haskell Garrett leading the way with 5.5 sacks and junior defensive end Zach Harrison leading the way with eight tackles-for-loss.

Twelve different defensive lineman recorded at least one sack for Ohio State in 2021, while 13 recorded at least a half of a tackle-for-loss.

However, that pressure up front was kind of erased in the final four games of the season, recording only three sacks against Purdue, Michigan State, Michigan and Utah combined, two of which were by defensive linemen: Garrett and freshman defensive tackle Tyleik Williams.

In Ohio State's two losses this season to Oregon and Michigan, the Buckeyes recorded no sacks and only one tackle-for-loss.

In the run game, Ohio State was fine, allowing 126.8 yards per game and 3.7 yards per rush, but 17 touchdowns: fifth-most in the conference.

In its two losses, the Buckeyes allowed an average of 283 rushing yards and an average of 7.2 yards per rush with nine rushing touchdowns.

There were points where Ohio State looked like it had one of the top defensive lines in the country: shutting down Michigan State's run game, recording five sacks or more against Akron, Maryland, Indiana and Nebraska.

But while it still has potential with Jim Knowles heading into 2022, it didn't finish on a high note, showing a lack of consistency in both the pass rush and rush defense.

Grade: C+

There's been a lot of changes to Ohio State's linebacker room in 2021.

In the span of a week early in the season, the Buckeyes lost two members of the room to the transfer portal: Dallas Gant and K'Vaughan Pope, who exited the field during the middle of the Akron game, being dismissed from the team days later.

As the room got smaller and smaller over the course of the season, leading to former running back Steele Chambers to join the room prior to the start of the season and former tight end Cade Stover to join the room fully ahead of the Rose Bowl against Utah, opponents got used to taking advantage of passing to the middle of the field between the linebackers and the safeties, leading to the third-worst pass defense in the Big Ten and finishing as one of five teams to allow opposing quarterbacks to record higher than a 60% completion rate.

That, along with rough run-fit performances against Oregon and Michigan really made this a problem room for the Ohio State defense in 2021.

It was a room that saw a bit more improvement in the Rose Bowl, with Stover looking right at home in the middle of the defense and Tommy Eichenberg taking over as a tackling machine, despite four missed tackles against Utah.

But this is a room that needs work, a room that will be in the middle of Knowles' revitalization of the Ohio State defense in 2022.

Grade: D

Ohio State's pass defense was not very good in 2021.

The Buckeyes finished with the third-worst pass defense in the Big Ten, allowing an average of 246.2 yards per game, was one of five teams in the Big Ten to record more than 20 passing touchdowns and was one of five teams in the conference to have an opposing quarterback completion percentage higher than 60%.

Like the linebackers, the approach of opposing pass offenses seemed to gravitate toward the middle of the field from opposing slot receivers and tight ends. Players like freshman cornerback Denzel Burke and redshirt junior cornerback Cameron Brown were actually solid from the outside, allowing 44 receptions on 98 targets for 533 yards and no touchdowns. That's a 44.8% completion rate for an average of 38.1 yards per game with no scores.

This happened while opposing quarterbacks torched the middle of the field, like the nine receptions on nine targets for 69 yards and a touchdown Purdue put up against Marcus Williamson or the 12 receptions on 13 targets for 208 yards and two touchdowns Lathan Ransom allowed against Tulsa and Nebraska.

It was where Ohio State was most vulnerable, allowing for high-accuracy and explosive performances in the passing game, which, for the most part, Ohio State was able to mask with high-octane passing performances of their own.

But Ohio State was exciting too defending the pass: finishing fifth in the conference with 12 interceptions, but finishing ties for first with four interceptions returned for touchdowns.

The Buckeyes had holes in its defensive backfield, holes that Knowles will try and fix heading into 2022. But it had its high points too, points that Ohio State can build off of.

Grade: C-

Ohio State's defense wasn't good in 2021.

It's why it finished ninth in the league in scoring defense, allowing 22.8 points per game. It's why it finished ninth in total defense, allowing 372.9 yards per game, 5.6 yards per play — one of six defenses in the Big Ten to average more than 5.5 per play — and 38 touchdowns.

It was enough to mask at points by the high-octane offense, and even enough for Ohio State to come back from, showing its potential in games against Michigan State, Indiana, Akron and Maryland.

But it was just examples of what could be, showing its struggles against Oregon, Tulsa, Michigan and in the first half against Utah, the struggles that Knowles will try to fix starting now.

Grade: C-