COLUMBUS — Throughout his time at Ohio State, defensive coordinator Jim Knowles has been asked various questions lauding his outfit for being near the top or leading the country in one statistical category or another.

On Tuesday, he was reminded that the Buckeyes have the country's best scoring defense and the best pressure rate without a blitz.

"Never satisfied," Knowles said.

So he's with anyone who's watched the starts the defense has had the last two weeks and knows that things need to start faster.

Overall, Ohio State's defense has been excellent against overmatched opponents. It's allowed only three touchdowns while ranking No. 2 in stop rate (how often it gets off the field) and No. 2 in yards per play.

But Knowles is fixated on the fact that his defense allowed 4.3 yards per play and two touchdowns in the first half against Marshall two weeks ago. It also allowed nearly seven yards per play in the first half last week against Michigan State, needing two turnovers deep in its territory to keep the Spartans from adding more than the lone touchdown they scored in Ohio State's 38-7 win.

"We’ve started slow the past couple weeks," Knowles said. "I blame myself for that. There are thousands of permutations of what can happen. You go back to how many times I practiced that, how many times I showed that guy that technique against that play or that route? That’s happened a lot in my career, that early in games you get some things you weren’t predicting. You always go back and fall to your training. You have to look at those failures, which come back to me, and continue to be exact in what I’m training and how predictable we’re being."

Ohio State has shut down opponents in the second half of games. Michigan State averaged 2.8 yards per play in the second half last Saturday. But Knowles knows that future opponents could do a better job of taking advantage if his defense continues to be slow out of the gates.

The focus then is on getting to those adjustments quicker.

"The craziest thing about our profession is that you can work on things all week and then show up in the game, and they’re not there," Knowles said. "But our job is to create a practice that mimics the game. That’s where you spend all of your time. It’s success through scripting, you’re trying to predict what they’re doing to do … and then you see what’s actually happening. You have to move on and adjust."

Here are more takeaways from Knowles' press conference on Tuesday:

Sonny Styles' move from safety to linebacker has been met with mixed results through four games. And it felt like Michigan State was explicitly targeting the third-year defender at times in the first half.

Knowles said Tuesday that he isn't alarmed by what he's seen from Styles thus far.

"I’m very pleased with Sonny," he said. "I think he’s being put into a lot of different situations playing Sam, playing Will, and Mike. All of those positions have their nuances to them. Sometimes when you see him, or any of our players, being off on a play or looking like they’re out of position, that goes back to me, training, and coaching."

If the staff has concerns about Styles, that's not reflected in the snap counts. He's played the most linebacker snaps and the fourth-most snaps of anyone on the defense. Despite the rise of second-year linebacker Arvell Reese, it's clear that the two linebackers who Knowles and position coach James Laurinaitis trust the most are Styles and Cody Simon.

Styles had some missed tackles against Marshall and then was picked on a couple of times as a pass defender against Michigan State while also, at times, seeming confused by how to fit up the run.

There have been other moments where Styles has looked like the player Ohio State expects him to be, and there's been no thought of pulling the plug on Styles at linebacker after only four games at the position — a strong endorsement considering the staff has seemingly moved C.J. Hicks down the pecking order already after a slow start.

"He’s employing myriad techniques playing all three positions," Knowles said of Styles, "and there’s a lot of nuance to it. We’ve gotta keep doing a better job of coaching all of the details."

Styles and the linebackers will be tested this week against Iowa and running back Kaleb Johnson, who is No. 3 in the country in yards after contact.

"What we need to see better is tackling," Knowles said. "Our linebackers need to continue to become better tacklers, and particularly this week, knock-back tacklers. This running back is the king of turning a two-yard gain into a four- or five-yard gain, which then leads to second-and-5 and third-and-2. We need to continue working on our tackling with an attitude of knocking people back.'

Jordan Hancock and Lathan Ransom both thwarted likely scoring drives for Michigan State last week by taking the ball away from Spartans players deep in Ohio State territory.

Hancock ripped the ball away while tackling tight end Jack Velling. Ransom punched the ball away from quarterback Aidan Chiles as he was attempting to avoid pressure.

"You saw two big plays last week that we’ve spent a whole spring and a fall camp training for those two plays," Knowles said. "The one that Jordan ripped out and Lathan with the punch, those are deliberate. Those do not happen accidentally. We try to train everybody, but some guys are better than others. Lathan Ransom is lethal with that, and I want him to keep it up."

Ohio State isn't among the nation's leaders in takeaways this year, but it is getting them an accelerated clip compared to last year. The Buckeyes have three takeaways so far, three interceptions and three fumble returns, and had 11 in 13 games last year.

As stated earlier, Ohio State leads the nation in pressure rate without blitzing, per Sports Info Solutions. That means the Buckeyes have generated the most quarterback pressure while sending four or fewer rushers.

In all situations, they're No. 8 in the country in pressure rate and No. 2 in sack rate.

The Buckeyes sacked Michigan State four times, with three coming against the starting quarterback, Chiles. They're No. 11 in the country in sacks per game.

Still, there's a sense that the pass rush could be better.

"They are executing what’s called," Knowles said. "We gotta tighten up our coverage. We need that extra second because the guys are getting there."

Knowles has relied a lot on off-coverage through four games. Without that, the sack totals could be even higher.

"That’s a constant adjustment," Knowles said. "We’ve been solid on explosive plays, so you can’t forget that. That wins games. But do we need to be pressed more? Yes, we do. We need to keep working that in, but we gotta balance it."

This week's opponent, Iowa, has been good thus far about limiting sacks, ranking No. 39 in the country in Pro Football Focus' pass-blocking efficiency metric. However, the Hawkeyes don't have much in the way of game-breaking receiver talent, which should allow Ohio State's corners to play more aggressively and perhaps help OSU's pass rush get to the quarterback more.