Ohio State defensive coordinator Luke Fickell has been the target of much criticism because his unit is performing far below expectations.

He even caught flak last week from a pizza delivery guy.

An employee of Laconos Pizza in Columbus reportedly was fired after making an off-the-cuff remark to Fickell’s wife, Amy, about how poorly the defense was playing. The incident became a hot topic on Twitter, and OSU issued a statement saying the Fickells only reported the incident after being called by the store manager.

The 11th-year OSU assistant knows his family has been portrayed as being thin-skinned and responsible for a person losing his job, but Fickell shrugged off the accusations.

“Nothing needs to be said. Our whole philosophy is don’t whine, don’t complain, don’t make excuses. I think I said it a million times (to the team) last year,” said Fickell, who was interim head coach in 2011. “My 5-year-old knows that, my wife knows that, we’re all in the same boat. We would never whine, we would never complain.”

After a pause, Fickell smiled and said, “I actually agree with him.”

The Buckeyes’ porous defense was shredded in a 52-49 win at Indiana, which scored its most points against OSU since the series began in 1901. But while he’s being vilified by fans, Fickell said he’s immune to what others are saying about him.

“If you can put more pressure on me than I put on myself — I don’t know how you could,” he said. “We could give up 14 points and, for some reason, I’m not going to be able to sleep at night because I’ll be thinking about what I could have done better.”

Fickell, who also coaches linebackers, is making $750,000 this year (tied with Michigan’s Greg Mattison for the most among Big Ten assistants). He became defensive coordinator under Jim Tressel in 2005, and the Buckeyes finished in the top-five in total defense in four of the next six years, including No. 1 in 2007.

But OSU is 69th nationally (out of 120 teams) this season, and opponents have exploited a weakness at linebacker with spread offenses.

“They want to put the ‘backers in positions where they have to make plays inside the box and outside the box,” Fickell said. “Obviously, there are things we haven’t handled very well this year.”

Fickell cited a lack of depth because of injuries, but he also pointed out that the 2009 recruiting class was highly touted but has produced few plums. The headliner of the class was linebacker Dorian Bell, a five-star prospect from Pennsylvania who had off-field troubles and transferred to Duquesne.

“The thing we’re missing is that fourth-year junior or fourth-year senior,” Fickell said. “You see (reserve quarterback) Kenny Guiton go into the game and do an unbelievable job as a back-up. He’s a fourth-year guy. He’s been around, he’s grown, he’s matured. Most of our fourth-year guys — we’ve got three who ‘medicaled’ (left the program with career-ending injuries). You say, ‘Boy, we wish we had those guys.’

“That’s where we’re counting on some truly young guys to step up, and maybe they aren’t ready yet.”

Another linebacker underperforming so far is sophomore Curtis Grant, once the second-ranked recruit in the nation. He was the starter for the first three games but has been demoted to special teams.

“He’s been here a year and a half, and he’s still trying to figure it out. Sometimes it takes time,” Fickell said.

The results have gotten so dire that coach Urban Meyer has begun taking a hands-on approach with the defense for the first time this week.

Fickell doesn’t seem threatened.

“He’s come over more, but he’s always been involved,” Fickell said. “I think he has the ability to get over there and do motivational types of things and point out some things and make things uncomfortable at times, but that’s how you grow.

“I think it’s been a good thing and, hopefully, he continues to spend a little more time with us. (The issues are) obvious, but sometimes when it comes from the top down, it becomes a little more obvious.”