Notre Dame's historic undefeated 2012 season was due largely to the impenetrable, top-ranked Irish defense. While head coach Brian Kelly caught most of the headlines, an equal amount of credit is due to defensive coordinator, linebackers coach and assistant head coach Bob Diaco.
The 39-year-old defensive coordinator has been Kelly's right-hand man since their days together at Central Michigan, following him to Cincinnati and finally Notre Dame.
Diaco's football education began early, telling Angelo Di Carlo of wndu.com:
You get habitized from when you are a kid---I can remember my dad when I was 8-years-old, pounding into my head the ideologies of defense, and making me repeat them to him---on demand.
Clearly, his father's education has paid off. The former Iowa player won this year's Broyles Award—an award given to the best assistant coach in college football—and was a semifinalist last year.
Diaco's skills have not gone unnoticed. Boston College interviewed him (per EagleAction.com's Mark Blaudschun) to replace head coach Frank Spaziani—a position that was eventually filled by former Temple Owls head coach Steve Addazio.
It comes as little surprise there is so much buzz surrounding Diaco. His defense finished its regular season ranked first nationally in points allowed (10.33), sixth in total yardage (286.8) and fourth against the run (via USA Today).
Many Notre Dame players credit Diaco with strengthening the Irish defense. "Our defense is strong because of him," captain and Heisman runner-up Manti Te'o told USA Today:
He focused on the little things. People tend to focus on X's and O's, schemes. Coach Diaco believes if I can coach my players to be the best players they can be, I can call any play and it doesn't matter what the offense does because he coached us enough that we will dominate no matter what.
"HA-- Coach Diaco is pretty nuts," then-sophomore Kapron Lewis-Moore said to Di Carlo. "When you look at him, he doesn't seem like he would be crazy, but he's a crazy guy on the field."
The much-beloved defensive coordinator will have his work cut out for him in 2013 when defensive stars Manti Te'o, Jamoris Slaughter, Kapron Lewis-Moore and Zeke Motta all move on to the NFL.
Here's how he must adjust his game plan this season to compensate for the losses and address other issues that dogged the Irish defense in 2012.
The most obvious issue Diaco will face is the defensive backfield, the team's Achilles heel in 2012. Outbound senior Zeke Motta will leave a big hole in the backfield that Diaco will have to fill. He may want to consider pairing 5-star recruit Max Redfield (per Rivals) with Matthias Farley as a starting safety. Whatever his decision, he has to accelerate coverage against the pass.
Speaking of pass coverage, starting cornerbacks KeiVarae Russell and Bennett Jackson—the top returning tackler from last season—will both return to their positions this fall.
Diaco needs to build on the experience his returning players will bring to the backfield to focus on defending against the pass.
As far as the front seven, Diaco must prepare his highly touted 2013 recruits to live up to the legacy left by one of the most celebrated defenses in Notre Dame history.
The most obvious loss on the D-line is star linebacker Manti Te'o. Te'o's heir apparent is 6'3" Jarrett Grace, who—with just 12 tackles to his name—will need a fair amount of direction from Diaco to live up to Te'o's legacy.
All is not lost, however, as linebacker Prince Shembo, nose tackle Louis Nix and defensive end Stephon Tuitt will all return to the defensive line; and former 4-star recruit Sheldon Day (per Rivals) will replace Kapron Lewis-Moore as a defensive end.
While the front seven was rock-solid for most of the season, the BCS title game exposed issues Diaco will have to deal with if he ever wants to take home a national championship. Adjusting the play-calling to compensate for the Eddie Lacys of the world will make the Irish a top defense and definitely put them in the hunt for the national title.
There is no shortage of defensive talent on the Irish defense this season, but Diaco must build out of the backfield and prepare the front seven for the big, physical running game of the SEC if the Irish want to be contenders in 2013.