There is an ample collection of running backs at Georgia Tech — 22 of them to be precise. There are also 13 former high school quarterbacks, many of them recruited because they were usually the best athletes at their high schools and capable of playing multiple positions.

What the Yellow Jackets do not have are tight ends or pro-style pass-blocking offensive linemen who are about 6 feet 4 inches and 315 pounds. Nor do they have a pro-style quarterback capable of standing tall in the pocket and throwing the ball 60 yards downfield.

The reason is simple. The Yellow Jackets, the nation’s best rushing team, run an option offense out of a formation resembling the Wing-T. The four-back setup does not require a tight end but does demand plenty of players capable of carrying the ball and lighter, more mobile offensive linemen. Georgia Tech recruits accordingly.

This can be a problem for the Georgia Tech defense, however. Without a conventional college offense to practice against, or, at the very least, comparably sized bodies to simulate one, the Yellow Jackets defenders are frequently forced to improvise.

Ted Roof, Georgia Tech’s defensive coordinator, used a tall defensive end as a stand-in for a Notre Dame tight end when the Yellow Jackets prepared for last week’s loss to Notre Dame. Other players said they sometimes asked offensive teammates to simulate blocks and movements they had picked up while studying video.

“It’s tough,” defensive tackle Adam Gotsis said, “just because we don’t have the 6-5, 320-pound O-linemen on the scout team, or even our starting team.”

That is mostly because the culture of Georgia Tech football revolves around the unconventional — but spectacularly successful — option offense directed by coach Paul Johnson. The Yellow Jackets have led the ACC in total offense three times in Johnson’s seven seasons, despite a minimal contribution from the passing game. During its 11-3 season in 2014, which included an Orange Bowl victory over Mississippi State, Georgia Tech averaged 56 run attempts and 14 pass attempts per game.

There is little question that an assertive run game has been the main reason Georgia Tech has advanced to three ACC championship games under Johnson. It may do so again this fall; the Yellow Jackets currently lead the nation in rushing, at 457.5 yards a game.

But the team has finished an average of seventh in the ACC in total defense over Johnson’s seven seasons. Part of that might be because, just as opponents have trouble simulating and preparing for the maze of runs they can expect from the Tech offense, the Yellow Jackets have trouble preparing for opponents who run a spread passing offense or pro-style running game.

“We just work with what we have,” defensive end Rod Rook-Chungong said. “We watch a lot of film, so if I need something I’ve seen on film I will tell the lineman I am in front of in practice, ‘I think the guy on me does this, this and this, so I need you to do this same block.’ I tell them what I’m looking for. They do a great job getting us ready.

“It’s bittersweet. Our scout team linemen are shorter linemen than we might see, but we’re able to work on our leverage all week, staying low. You just have to adjust in the game.”

The Tech offense is also hard to simulate, but preparing for it is not the same degree of challenge. Opponents can mirror Georgia Tech’s offensive formations and plays easier than the Yellow Jackets’ defense can mirror the size and bulk of an opponent like Notre Dame, or the players and offenses they will see later this season in games against teams like Florida State, Miami and Georgia.

Georgia Tech surrendered an average of 6.3 yards per play last season, when it ranked 62nd nationally in rush defense and 87th overall in pass defense. That led to the usual ridicule that Tech’s best defense was its offense, since its ground-chewing, time-eating run game kept the opposing team’s offensive players stewing on their sideline waiting to get the ball back.

But Rook-Chungong said this year’s defense was primed to change things. Georgia Tech returned eight starters from 2014, plus the starting nose tackle Jabari Hunt — a 6-foot-3, 292-pound redshirt senior who was academically ineligible last season.

“We’ve come in with a chip on our shoulder, especially after last year,” Rook-Chungong said.