Safeties are not often regarded as the cornerstone of a defense.

Sure, it’s important to have reliable ones as the unit’s last line of defense, but linemen, cornerbacks and linebackers are often deemed more crucial.

That’s why it was telling when new Ohio State defensive coordinator Jim Knowles placed a premium on the safety position after the team’s first spring practice Tuesday.

“This is a safety-driven defense,” he said. “It really is.”

Knowles and coach Ryan Day believe the position could be stacked. That wasn’t the case last year, at least after Josh Proctor was lost to a season-ending leg injury against Oregon in the second game. The Buckeyes gradually evolved away from a single-high-safety approach after Bryson Shaw replaced Proctor to use a more conventional alignment with two deeper safeties.

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The Buckeyes plan to use three safeties in their base defense. The bandit will play on the boundary side, or short side, of the field. The middle safety is called the adjuster because it’s his duty to make adjustments based on the offensive formation. The nickel, which was called the cover safety last year, lines up against the slot receiver.

Assuming Proctor becomes healthy, he would be in line to play the adjuster position, but he’ll have competition. The plan is for Proctor to ease into spring practice.

“When Josh went down early in the season, there was a little bit of a panic, but some guys stepped up and did some really good things,” Day said. “It certainly will be great to get him back and get him healthy again. But we also have some other guys back there that have had really good offseasons and played well last season. Not good enough, but they have another year under their belt, and they'll come back and be stronger this year.”

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Ronnie Hickman, who played the hybrid safety/linebacker position known as the bullet last year, had 100 tackles to lead the team by a wide margin. He would seem to be a fit at the bandit position.

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“I just think he is a heads-up guy,” Knowles said. “He understands defense. He communicates. He's got a great personality. He's everything I want in a safety.”

Knowles has a familiar face as the leading candidate to play nickel. Tanner McCalister was a two-year starter for Knowles at Oklahoma State before becoming a graduate transfer to the Buckeyes in the offseason. As the Buckeyes learn the new defense, McCalister, two-time Academic Big 12 player, could be invaluable to his teammates.

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“He's that guy who can talk to the players not only about scheme, but he can talk to him about me, too,” Knowles said. “Day 1, if I go from being Mr. Calm to running around and screaming, he can say, 'Hey, that's just Knowles. Chill out. He's fine. That's just the way he is. Don't take it personal. He just wants you to get better.'

“To have a guy their own age who knows me as a person, he's going to be able to tell the guys a lot about me, not just as a teacher and scheme — and he can teach the scheme —but he can tell them about me and how I operate and who I am.”

Knowles also mentioned another player, Kourt Williams, that he seems eager to get on the field. At 6 feet 1 and 220 pounds, Williams could project as a linebacker, but Knowles wants to keep him at safety, specifically the bandit.

“We feel like he can get into the run fit there when we want him (to),” Knowles said. “We feel that he's a leader. When I watched him in the weight room and work, he's a worker, he's a leader, so I like him. I like him with more depth and vision to be able to see the ball and to control the movements of the secondary.”

Ohio State wants to have positional flexibility, so players could move around. Asked if Hickman and Williams could be on the field at the same time, Knowles replied, “Yes. The answer is yes. I do envision them both playing together.”

Bill Rabinowitz covers Ohio State football for The Columbus Dispatch. Contact him at brabinowitz@dispatch.com or on Twitter @brdispatch.

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This article originally appeared on The Columbus Dispatch: Safeties key to Jim Knowles' Ohio State football defensive scheme