Ohio State fullback Zach Boren was once an all-state linebacker at Pickerington Central High School and recalls many a collision with Michigan State tailback Le’Veon Bell, who starred at Groveport Madison.

Bell was known in Columbus-area prep circles as someone capable of trampling opponents like a monster track rumbling over a pile of bashed-up cars. But Boren led his team to victory and had some personal success — even though he emerged from their encounters with more than a few welts.

“He’s a powerful runner,” Boren said. “I think he’s stayed true to himself from high school to college. He’s a workhorse. In high school, they’d feed him the ball 30-40 times, and it’s the same at Michigan State. He’s a Heisman candidate.”

Asked if he’d be willing to share some tackling tips with his defensive teammates, Boren replied, “Yeah, if they ask me.”

His fellow Buckeyes probably won’t bother to inquire about Bell, only because they’ve seen enough of him on TV and video to know what they’ll be facing.

The 6-foot-2, 245-pound junior is third nationally in rushing with an average of 152.5 yards per game, and he’s second in total carries with 117.

“He reminds me of Ron Dayne — even more athletic,” OSU coach Urban Meyer said, referring to the former Heisman winner from Wisconsin. “He’s a guy that’s extremely powerful, times up his blocks very well and runs through tackles. And you see athleticism that usually people that size don’t have.

“To tell you of his athleticism, he returns punts as well. That might be the biggest punt returner in the history of college football.”

The Buckeyes will be facing their most challenging test yet on defense — and they didn’t exactly ace any of their previous exams this season.

They’re ranked last in the Big Ten and 71st nationally in total defense (allowing 394.8 yards per game). They’re 33rd among 120 FBS teams against the rush and a dismal 104th in stopping the pass.

“That’s very alarming,” Meyer said. “That’s not Ohio State defense over the last 10 years. Last year was not great, but the previous years before that was as good as there is in the country. … That’s something that’s got to change real fast.”

The OSU defensive line hasn’t been applying consistent pressure, and opponents have exploited the generally soft coverage in the secondary. But the unit’s biggest weakness so far may be at linebacker.

Sophomore Curtis Grant, considered the second-ranked recruit in the nation in 2011, was the starting middle linebacker for the first three games but was replaced last week by senior Storm Klein.

Sophomore Ryan Shazier and senior Etienne Sabino are the outside linebackers and lead the team in tackles with 40 and 28, respectively. But they’re both first-year starters, and their inexperience has led to some missed assignments.

Although he’s aware of the criticism about that position group, Sabino said: “I try not to feed too much into that. We’re probably our hardest critics, and we’re going to keep working. But we will get better.”

The Buckeyes are almost giddy about finally being able to face a traditional offense this season. The Spartans try to bludgeon foes with a power running attack, while OSU’s first four opponents were spread-the-field finesse teams.

“I think our defense is kind of built for this,” Meyer said. “It’s not built for sideline-to-sideline dinking and dunking.”

A glaring shortcoming for the Buckeyes, though, has been blown tackles. And that’s a skill that’s needed just as much in the trenches as it is on the perimeter.

“I don’t think our issue is point-of-attack tackling. I think our issue is space tackling,” said OSU co-defensive coordinator Everett Withers, adding that the Buckeyes need more defenders racing to the ball.

“I call them in-traffic tackles and out-of-traffic tackles. In traffic, I think we’re pretty damn good. It’s just when we’ve been out there in space, we miss a few. But I think if you turn on any game in America, they’re going to miss a few out on the edges in space. It’s just a matter of whether those other guys are coming.”