SOUTH BEND — Less than a week after new Notre Dame head football coach Brian Kelly unveiled his 3-4 defensive scheme, the pieces of his defensive coaching staff have begun to fall into place.

Greg Johnson of the Grand Rapids Press and Justin Hoff of mlive.com are both reporting that Grand Valley State head coach Chuck Martin will join the Irish as their new defensive backs coach.

Kelly said he hopes to announce the entire staff shortly after his old school, Cincinnati, plays Florida in the Jan. 1 Sugar Bowl. The only official announcement to date was one detailing the retaining of running backs coach Tony Alford from deposed coach Charlie Weis’ staff.

The 41-year-old Martin succeeded Kelly as Grand Valley’s head coach after the 2003 season and has fashioned a .914 winning percentage (74-7) since, with two national titles (2005, 2006). The Lakers fell a touchdown short of making it three this season.

Martin is a former Division III All-American free safety at Millikin University, where he earned an accounting degree in 1990. The Park Forest, Ill. native was also an all-conference kicker for the Millikin football team and was a standout for the school’s basketball squad.

As far as the 3-4 look (three down linemen, four linebackers) Kelly will employ, it’s the third scheme change the Irish will have undergone since 2007.

“We’re extremely flexible within that 3-4 structure,” Kelly said last week in a small group interview. “I felt over the past 4-5 years, as a head coach, increasingly running multiple personnel packages (into a game) on defense took away from our skill development.

“The 3-4 allows you to keep your personnel on the field longer and allows that repetition to occur. And if you get into a game where you need to strengthen yourself, you can drop one of those hybrid players down and play in a four down-(lineman) defense.

“It gave me, as a head coach, more flexibility and allowed us to develop our players better, in my estimation.”