The computer chips in the shoulder pads confirmed Mike Gundy’s suspicions.

The defense appeared slower than normal against Kansas and was failing to do important things right. Tackling, assignments, getting off blocks. The rush defense, especially, gave up too many big plays and lacked execution.

After looking at the data on the chips, Gundy said the speed of the defense was slower against the Jayhawks than any other game this season. And it showed. KU manhandled OSU’s defensive line and created huge running lanes. After that, arm tackles, poor angles and missed assignments at linebacker allowed the Jayhawks to surpass 350 yards rushing.

Rush defense, which was once the strongest, most reliable part of OSU’s defense, has now become its most glaring issue.

“We missed more tackles in that game than we have,” Gundy said. “Quite honestly, we looked tired, in my opinion.”

Things weren’t always this way. The Cowboys gave up just 118 rushing yards per game over their first five games, 3.3 yards per carry, which would rank top 25 nationally at this point in the season. Boy, does that feel like a long time ago.

In the four games since, OSU has given up 244.5 yards a game, at a rate of 6.2 yards per carry – slating it as the 100thranked rush defense in FBS. So what’s went wrong?

Gundy placed some of the blame on the injuries that have plagued the Cowboys. Defensive tackle Brendon Evers is gone for the season, defensive end Brock Martin has missed time and lineman Tyler Lacy has battled health. The excuse is there, but defensive coordinator Derek Mason isn’t having it.

“I’m not going there (injuries),” Mason said. “I think that’s the season. I think everybody deals with the same thing. Everybody’s beat up.”

Again, what’s the issue then? Outside of Evers, the defensive front is nearly identical to that of last year’s defense that gave up just 87 rushing yards per game. The defensive unit averaged more than 10 tackles for loss per game over the first five games but has averaged just three since. There’s not the push into the backfield to stop runners like there was early in the season.

Coaches have had to adapt to youth at linebacker, as well. Mason Cobb and Xavier Benson were forced to fill the voids of two NFL linebackers, who were big assets in last year’s staunch run defense. This year’s defense doesn’t yet have that level of cohesion. Mason said it will require more from everyone to improve.

“Here’s the deal, you can make every adjustment in the world, but this is still a run and hit game,” Mason said. “Schemes are schemes. Players make schemes come alive. When you’re running similar or same schemes, you need better execution. And so we’ll scheme it better, and we’ve got to continue to ask for better execution all the way around.”

Practices this week have sounded different. That better execution is being asked for.

“A whole lot of yelling,” said defensive end Collin Oliver.

But it comes from a healthy place. Oliver said his unit has been more vocal this week and has held each other accountable. The defensive line is the first defense against the run, so they hold themselves responsible for problems defending the rush. If someone is slacking or missing assignments in practice, they’re getting called out.

Part of that mentality trickled down from Sunday meetings, where Gundy was blunt with his coaching staff. They needed to get better.

“They weren’t big Gundy fans when the meetings were over,” Gundy said. “But that’s my job, because we have to share the deficiencies with the team. We can’t just push it on the team because it’s not all on the team. We could have coached better, also.”

Oliver said coaches are grading practices now and doing their part to hold players accountable, and he appreciates that. The team needed to refocus, rejuvenate and correct issues that, frankly, haven’t been a problem or needed addressing recently.

But whether it’s injuries, scheme, execution or a combination of it all, the rush defense has lost its touch over the last month.

“It is pretty frustrating, I’m not gonna lie,” Oliver said. “When you know that we’re better than what we’re showing out there, and we’re way better than what people are saying that we are, it is frustrating seeing all that. All I know to do is just fight back.”