NASHVILLE, Tenn. -- When Jim Harbaugh was in search of a defensive backs coach in 2010, he wanted someone who preferred a 3-4 defense. Stanford was making the transition to that scheme at the time. Harbaugh had already hired longtime NFL assistant coach Vic Fangio to run the defense, and he wanted like-minded assistants.

Enter Derek Mason. The up-and-coming coach had spent the last three years in the NFL with the Minnesota Vikings, and though they ran a 4-3, Mason knew his way around a 3-4 defense dating to his early days at Bucknell University.

“I think it's a different mentality,” Mason said. “I think it's a difference of philosophy in terms of what we look to do. Obviously when you go from a four-man front to conceivably what's a five-man front, there's a different mentality in terms of how you attack the line of scrimmage and what you're looking to do with your structure.”

After Harbaugh left for the NFL, Mason was promoted to co-defensive coordinator at Stanford and put his own stamp on the Cardinal’s defense. Now, four years later, he’s bringing that defense with him to Vanderbilt, except that this time he’s in Harbaugh’s shoes. For the first time in his career, he’s the head coach.

Like his old boss, Mason went out and hired defensive coaches who share the same philosophy. And who better to serve as his defensive coordinator than David Kotulski, the inside linebackers coach at Stanford and the man who introduced the 3-4 defense to Mason when the two were together at Bucknell 15 years ago?

Bucknell was Kotulski’s second defensive coordinator job. Vanderbilt will be his sixth.

“We're very excited about the young men that we have,” Kotulski said. “Is there a transition point? Yes. And we put a lot of stuff in, no question about it. At this point in time, we just have to keep on playing faster as a unit, and it will come as we keep on getting better.”

Changing defenses is never easy, but Mason knows what to expect as this Vanderbilt defense goes through the same transition.

Defensive linemen who are used to being on the edges are now being asked to take on blocks in order to free up linebackers. Defensive ends who have always played with their hand in the dirt are being asked to drop back and play in space.

“I think it's a three-phrase approach,” Mason said. “I think it goes from spring into summer and then back to fall. What happens is right now they're learning it for the first time. When you come back in fall camp, they will now have heard it for the third time, and I think hearing it for the third time, that's when it starts to go.

“I really believe that where we're at right now is just the first phase of it. We'll be fine.”

Veterans Caleb Azubike and Kyle Woestmann are among those in unfamiliar territory this spring.

As defensive ends a year ago, Azubike shared the team lead in tackles for loss (9.5), and Woestmann finished with a team-high six sacks. In the new defense, they’re both moving to outside linebacker, where they will play standing up for the first time.

“We're learning a new scheme, obviously,” Azubike said. “But playing with this new coaching staff has made the process much easier because they understand the fundamentals needed. They don't rush you. They try to make sure you know exactly what to do in every single aspect of the game. With their help, there's very little we couldn't do.”

“The new staff is incredible,” Woestmann added. “These coaches are great X’s and O’s coaches. “They show us how the fits work and all the moving pieces that you draw up on the whiteboard. They do a great job really teaching us how to play football.”

As the Commodores adjust to the new defense, they’re doing so essentially without eight starters from a year ago, including two potential NFL players in cornerback Andre Hal and safety Kenny Ladler. It’s a unit that has talent, but is lean on experience. The goal is to develop leadership and game experience, but that will come with time.

“It's not a goal of winning championships right now,” Kotulski said. “It's about getting better each time. Now, bottom line, that's what we're talking about. We didn't come here to play for second. You play hard. You play fast. You have fun playing it. You compete and when you put all those pieces together, good things happen.

“Hopefully, we'll play a lot of important games as the years go on.”