HUNTINGTON, W.Va. -- Marshall might be the best in Conference USA in throwing the football, but it's not the only one that's good at it.
That's led the Thundering Herd to retool its defense in what's becoming even more of a pass-happy league.
The Herd has moved to a five-defensive-back lineup. It's a way to add athleticism to the field and counteract C-USA's penchant for putting the ball in the air. With some new additions to the secondary's roster, the group said they're quickly learning how to handle life with a more crowded defensive backfield.
Marshall Coach Doc Holliday said the move almost was out of necessity.
Of the 14 teams in the 2013 edition of Conference USA, seven were in the top half of the Football Bowl Subdivision in 2012 in passing yards per game.
Three of them - top-ranked Marshall, third-ranked Louisiana Tech and the 19th-ranked UAB - were in the top 20.
As C-USA offenses become more wide open, Holliday said defenses need to have enough players in the secondary to combat that.
"We talked all last year that it's no secret that, in this league - with the teams you have and the offenses you play - you've got to be very athletic on that back end," he said, "and you've got to have guys that can play in that nickel spot and still have two safeties who can cover and make plays in space. That's what it's coming to.
"It's a space game. Look around our league. With the exception of two or three teams, it's very similar to us. You've got to be able to match up and play those guys in space. For the most part, I think our guys have gotten a lot better doing that."
Thundering Herd defensive coordinator Chuck Heater's mission since he arrived in January has been to lead Marshall's defense into this new scheme.
It essentially puts three corners and two safeties on the field at the same time, removing a linebacker from the 11.
Holliday has said that strong safety D.J. Hunter will play like a linebacker at some points, and Heater said getting another corner into the lineup is essential for the five-man secondary to work.
"If you're going to be a man coverage team, which we are in part, and they put a third receiver in there, you can't cover him with a linebacker and you're at risk if you cover him with a safety," Heater said. "So you've got to put a corner-type player in there so when you do play man, you've got the right matchups."