In many ways, a football team’s defense is a lot like a well-running fire prevention system.

The front line is there to stop the fire before it starts. The linebackers are charged with running to the scene of the blaze once it breaks out. And if those fail, the defensive backs, safeties in particular, are expected to keep it from consuming the entire block — or in football parlance, going the distance.

As Ohio State goes about fixing the season-long affliction of giving up big plays, defensive coordinator Greg Schiano said Wednesday they are looking into tweaks at all three levels.

That’s keeping in mind, he said, that even in the stunning 49-20 loss at Purdue last week, the defense made a lot more good plays than bad. But 20 missed tackles by the Buckeyes were bothersome, Schiano acknowledged, adding that bad plays keep increasing the heat.

But one ploy in particular — bringing linebackers close to the line of scrimmage — has become the favorite topic around the whipping post. On numerous occasions this season, OSU linebackers haven’t been in position to make tackles on simple runs that get past the line of scrimmage.

“There (have been) times this year when we have walked up one linebacker into the line of scrimmage,” Schiano said. “We actually moved away from that last week. …

“But third downs, when you’re doing some exotic blitzes and things, we’re going to have them walk up. We always have. You get in the gaps. Most teams do that.”

There are positives to such an approach, Schiano said.

“The main one being getting double teams off your defensive line, instantly,” he said. “We thought as we went through the season we would get more and more comfortable with it. That hasn’t been case.”

That’s why at Purdue the Buckeyes limited its use “and picked our spots,” Schiano said.

But one spot in particular broke open the game. OSU was fighting to stay in it, trailing 21-6 early in the fourth quarter, when on third-and-9 at the OSU 42 the Buckeyes had linebackers Malik Harrison and Pete Werner creep up to the line.

As if an automatic reaction, the Boilermakers went with an inside zone run by D.J. Knox, who ripped through a huge hole up the middle created when Harrison was unable to shed a block. Knox then sidestepped safety Jordan Fuller on the way to the end zone.

“A lot of times what you see is the linebackers getting up near the line, and then they get caught up in the wash,” ESPN analyst and former OSU quarterback Kirk Herbstreit told The Dispatch.

More important, Purdue coach Jeff Brohm saw it in preparation.

“I thought their linebackers were good players, but they were up in the line of scrimmage a good bit,” Brohm said. “And if you could get past that first level, there was a bigger level between them and the safety because they play up so far.”

A tight game usually takes only a play or two to break open, so Purdue kept trying until, as Schiano said, and “the fourth quarter really got away from us.”

Besides Knox’s 42-yard run early in the fourth, the Buckeyes gave up another long TD run by Knox, a 40-yarder, and a 43-yard catch-and-run by speedy Rondale Moore.

Going forward — the Buckeyes resume play Nov. 3 against Nebraska — Schiano said there will be no drastic scheme changes.

Schiano noted that he and the defensive staff were rethinking linebacker walk-ups, but in general, “it’s eight games in, you’re not going to wholesale change your schemes, nor should we. But there are things we can tweak to help them.”

tmay@dispatch.com

@TIM_MAYsports