Allen Park — It wasn't that long ago, Miles Killebrew appeared to be a long-term safety solution for the Detroit Lions. But a season ago, despite being healthy and active for all 16 games, he didn't play a single defensive snap.

Last year was one of transition for the entire Detroit defense, switching to a new scheme under coach Matt Patricia. But there was an added layer to the shift for Killebrew, who was assigned a new position, moving from safety to linebacker.

The differences between playing in the box as a strong safety and a linebacker are subtle, in many ways. The constant between the two is the closer you are to the ball, the faster things happen.

Killebrew started at the bottom of the depth chart after the change and never really climbed out of that spot during the 2018 campaign. Still, he managed to play a critical role on the roster, and one that figures to keep him employed in the league for years to come, even if never manages to get back to being a regular contributor on a defense.

While Killebrew didn't play a defensive snap last season, no one on the Lions was on the field more than the 337 snaps he played on special teams, nearly 80 percent of the team's overall total.

"(He's) one of the guys that's out there in all four phases, which is critical for us as a team to have those guys," Lions coach Matt Patricia said. "Every single week that's a huge phase of the game. They dive into the game plans, they understand they help some of their teammates who are maybe on one or two phases. They're kind of the glue that holds all those different special teams together. The guys that are your core special teams guys are such a huge value to the team."

In the NFL, there is a history of players who can carve out long careers strictly as special teams standouts. In New England, where Patricia and Lions general manager Bob Quinn cut their teeth, wide receiver Matt Slater is entering his 11th season. A former fifth-round pick, he's caught eight passes during his career, just one more than his seven Pro Bowl selections as a special teamer.

If Killebrew could manage that type of longevity, even without a defensive role, he wouldn't be disappointed.

"I tell you what, if I'm in this league for 10 or 11 years, you come to me at that point and ask me if I had fun and I'll tell you, 'Yes,'" he said. "I must have been doing something right to make it that long. To make it 10 or more years in this league is hard."

That's not to say, Killebrew is content with that possible future now. He's still working hard to refine his skills as a linebacker, and his improvement has shown through on the practice field during training camp.

"I think he's really made some huge strides for us on the defensive side of the ball, through camp," Patricia said before Wednesday's practice. "He's made a lot of plays out there. He's gotten the ball out a couple times. He's forced a couple turnover situations, ball-disruption situations. We're really pleased with his work ethic right now and what he's trying to do with his growth."

During Wednesday's practice, Killebrew had a series of successful blitz reps working one-on-one against the linebacker, drawing some on-field praise from his coach.

"What it comes down to is what is needed," Killebrew said. "I'm trying to be like everyone else on this roster and make myself available for whatever is needed. One thing Patricia loves, (defensive coordinator Paul) Pasqualoni loves is versatility. He asks that of all his players. We don't know what roles are going to be needed next week, or even tomorrow. We're all just working on learning the entire defense, all the special teams if we're on special teams, so we can be plugged in wherever we're needed.

"I know one thing, guys that put the team first, they stick around. That's my goal, to put the team first."