A year ago this March, Manny Diaz was facing a crossroads. The husband and father of three was turning 40. His family was settling into a new town. He was getting used to a new job. And in the midst of it all, he was asking himself a daunting question: “Who am I?”

Facing a life over the hill, he wasn’t sure what lay on the other side.

In secluded Ruston, Louisiana, he was starting over. Far from the bright lights of his former home at the University of Texas, he was getting used to being defensive coordinator at Louisiana Tech, a program that had gone 4-8 the previous season under new coach Skip Holtz.

It was a curious move, dropping down into Conference USA. According to reports, Diaz had bypassed several Power 5 programs who wanted him as a position coach. But Diaz wanted to remain a defensive coordinator. He needed to so he could figure out what had gone wrong.

“When you get knocked back like that, you have to look at yourself and say, ‘OK, who am I?’ and not, ‘What am I trying to be?’” Diaz told ESPN.com. “You had to find the ability to say who are you and what do you believe in. And if you ever get the opportunity again, you have to stay true to that.

“Because when all of the sudden that changed, you know it didn’t work. ... You sort of went and became this thing. It looked one way at every stop and then differently at this place. OK, why?”

It went back to fundamentals, he explained.

“One of the greatest things about college football is there’s a million ways to do it,” he said. “You watch every Saturday and there are so many stylistic ways that teams choose to win football games: power running, four-wide, the possibilities are endless. But you have to be one thing. You have to be committed to one thing. Teams that are committed to a plan generally play for shiny things at the end of the season.

“If you don’t have that, if you don’t have the trust, if you don’t have a staff that’s committed to each other, those teams always tend to scratch their head and wonder why they’re not winning more.

“Everyone would understand that intellectually, but when you’ve been through it, it changes you. It changes what you’re willing to compromise yourself on.”

Back to being part of what Diaz described as a staff of common ideals, he thrived. Louisiana Tech won nine games and led the country in turnovers gained (40).

Shortly after winning the Heart of Dallas Bowl, Diaz got a phone call. An old friend was on the line: Mississippi State coach Dan Mullen. In what had to conjure flashbacks of 2010, Mullen asked if he wanted to return to his former post as defensive coordinator. Diaz said yes.

“It’s not a fun lesson to learn,” Diaz said of his fall from Texas and subsequent revival at Louisiana Tech. “But it reinforces who you are and what you believe in.”

He added: “It’s always easy this time of year to write the article, Hey, here’s this coach who has this great scheme. There’s no great scheme. If there was a great scheme, we’d all do it. What it was [at Louisiana Tech] was we were all bought in and all committed. We all pointed the same direction.

“That’s what I wanted more than anything.”

When Diaz returned to Starkville, he was blown away. It had only been a few years since he left, but it was as if everything had changed.

“The first thing is walking in, there’s no building here the last time I was here,” he said. “The stadium isn’t the same as it was the last time. This program is not the same program it was in 2010, and there’s no doubt you sense a different expectation from the players.”

But at the same time, it was as if nothing was different. The principles Diaz holds so dear were still intact.

“The message has remained consistent as far as how we’re going to win, who we’re going to win with and what our plan is to get it done,” he said. “What’s further appealing to me is that it’s based on something sustainable and not a flash in the pan.

“We’re trying to build to a level that we’re a main contender in the SEC West.”

That will take some work given that a large chunk of the defense is gone from last season, including linebacker Benardrick McKinney and defensive linemen Kaleb Eulls and Preston Smith. But even so, the cupboard isn’t bare.

Hoping that 2014’s “Pippens” become 2015’s “Jordans,” Diaz’s plan isn’t to overhaul the defense. As he said, “I’m just the conductor of the orchestra.”

But nonetheless, the expectations for both he and Mullen are ambitious. Because even after a record-breaking season in 2014, they want the bar set even higher.

“We’ve got to demand that we do better than we did,” Diaz said. “The reason is quite simple, because if you don’t then you’re really settling for being worse.

“Our players expect to show that our success here is expandable.”

It’s a tough task for a program that’s never won at a high level consistently, but at the same time there’s not a sense that success has changed Mullen’s beliefs. If it had, Diaz might not have come back.

He’s been through instability and he’s had enough of a lack of common direction. At 40 years old, he’s learned that you can’t waver on certain things.

“As you go through this, you get hardened,” Diaz said of his career. “You understand the things you can’t compromise on. You understand the importance of accountability. You understand the importance of toughness. But more than anything you have to understand the idea of trust. To me, a defense can’t be a defense without trust.”