IOWA CITY — On the back end of the Iowa defense, the notion of limiting big plays is no longer small talk.

The Hawkeyes gave up eight plays of 15 yards or more in last weekend’s 30-27 loss to Northern Illinois, continuing a recent trend that Iowa defensive backs want to stop.

“It comes down to being focused play in and play out. Last week, it came down to guys taking their minds off things for that split second and that’s what college football is,’’ safety Tanner Miller said. “It’s a game of inches and making a split-second decision. That’s the difference between giving up on a big play and getting an interception.’’

Improving those split-second decisions is an emphasis for the Hawkeyes as they work toward Saturday’s 11 a.m. game with Missouri State at Kinnick Stadium.

Beyond turnovers, coach Kirk Ferentz said the number of potential game-changing big plays allowed by Iowa ranked among the biggest concerns he had from the Hawkeyes’ opening-game performance.

“Giving up big plays, anything over 15, 20 yards, it’s tough to win consistently doing those things,’’ Ferentz said. “I think all of the things we saw hurt us are addressable, and it’s just part of the first game. Now, the challenge is what we can do this week to move forward.’’

Cornerbacks B.J. Lowery and Jordan Lomax share that objective.

While Lowery started nine games a year ago, Lomax spent the season on the sideline nursing a shoulder injury and saw his first game action Saturday since the 2011 Insight Bowl.

Lowery dealt with cramping issues during the game, something he said he has had issues with since high school, and Lomax dealt with a hamstring problem during the game.

Both expect to play this week, and both expect improved consistency.

“I thought we played aggressive as a defense. We had a few mistakes that led to a couple of breakdowns on coverage and that’s something that we have to clean up,’’ Lomax said. “The big plays were the difference between winning and losing and we can’t let them happen the way they did.’’

Lowery said the mistakes Iowa made provided Northern Illinois’ offense with life.

“We were in control, but we let them get free too many times and especially when the game was right on the line, we let them go deep on us and that can’t happen,’’ Lowery said. “We know that we’re going to face good players, but if we want to be a good defense we have to defend those guys and not give up the kind of big plays we gave up last week.’’

The foundation of the Iowa defense traditionally has been built on limiting long gains.

The Hawkeyes are finding that the foundation is being challenged more frequently.

Miller sees that as a byproduct of the growing number of high-tempo offenses that Iowa is facing, putting additional pressure on maintaining a consistent level of performance over an expanded number of plays.

“You’ve got to get your conditioning down and stay focused play in and play out for 80-plus plays, that’s what they are throwing at you with this high-tempo offenses,’’ Miller said. “You’ve got to get it down and stay focused for the whole game.’’

Lomax believes that focus is the difference.

“You can’t take a play off or you will get burned,’’ he said. “We’ve seen a lot of tape this week and we see where we can get better. If we can eliminate the big plays, control the offense that way, we can take control of the game. It’s something we have to do a better job with starting now.’’

There are changes in the depth chart this week, with sophomore Sean Draper and true freshman Desmond King moving into backup roles.

Most of the issues that Lowery said Iowa is dealing with this week are correctable.

“That’s the good thing, they are little things,’’ Lowery said. “But, we can’t let little mistakes lead to big plays. We have to clean some things up, and we will. We’ll get that done.’’

Ferentz counts on that, saying he likes the personnel Iowa has to work with in its secondary.

He believes time and experience are the solutions to reducing the number of big plays Iowa has allowed.

“Probably every coach in America is saying that right now, but that’s what it gets down to and that’s what practice is all about,’’ Ferentz said. “That’s what Sunday was about, seeing those things on film, going on the field and going through them, correcting them and then hopefully carrying that over the rest of the way for the next 11 games.’’