The number in parenthesis represents each player's remaining eligibility entering the 2012 season.
5th-year senior Kapron Lewis-Moore, 6'4" 306 pounds (1)
Sophomore Tony Springmann, 6'6" 300 pounds (4)
Notes: Springmann regularly rotates in both quarters of the first half and should again appear in the second stanza. He's also capable of providing relief at nose guard as needed. Lewis-Moore has played the best football of his four-year starting career over the last five contests, just two weeks after missing most of the Purdue contest due to a calf strain suffered on the game's first series.
Sophomore Stephon Tuitt, 6'6" 303 pounds (3)
Freshman Sheldon Day, 6'2" 286 pounds (4/5)
Notes: Tuitt ranks third among the nation's sack leaders (8.5) and second to Prince Shembo for the team lead in QB hurries (8). Day excelled early in a backup role, recording key defensive plays vs. Purdue (QB pressure that led to a Bennett Jackson interception), Michigan State (a sack and PD on back-to-back plays to push the Spartans out of scoring territory), and Michigan (a late sack to force a field goal). He's since maintained a regular rotation spot in the team's six-player defensive front.
Junior Louis Nix, 6'3" 326 pounds (3)
Junior Kona Schwenke, 6'4" 290 pounds (2)
Sophomore Tony Springmann, 6'6" 300 pounds (4)
Notes: Schwenke sees more time in the first half than second, he put forth his best effort of the season last week in Norman. Springmann provides insurance on the nose in addition to his role as a DE and 3-technique tackle. Nix has ascended to #2 or #2A among the team's top 10 players this season in a running Irisheyes.com ranking.
Junior Prince Shembo, 6'2" 250 pounds, (2)
Sophomore Ishaq Williams, 6'5" 255 pounds (3)
Notes: Williams has developed a dual-role in the team's nickel package, playing both defensive end in 4-man fronts and dropping to a nickel linebacker (coverage) spot when the nickel shows three-down as well.
Shembo was forced to play more in space last week vs. Oklahoma's up-tempo, spread, replete with dangerous athletes. Look for the natural pass rusher to come off the edge again Saturday vs. Pittsburgh. He leads the team with nine QB hurries this season.
Junior Danny Spond, 6'3, 242 pounds (2)
Sophomore Ben Councell, 6'5" 240 pounds (4)
Notes: Spond plays the vast majority of snaps while Councell has moved to primarily a special teams (kick return) role. Spond has also forged a role as the team's strong side linebacker (field side) in 4-3 fronts, with Dan Fox on the opposite flank. He remains on the field in nickel situations as well, often playing cornerback in bracket coverage (help from a safety).
Senior Manti Te'o, 6'2" 255 pounds (1)
Sophomore Jarrett Grace, 6'3" 240 pounds (4)
Notes: Te'o rarely leaves the field, starting in the nickel package as well. He leads the team with eight passes defended, 81 tackles, and five interceptions. Grace is his technical backup though most of the redshirt-freshman's playing time has come on the Irish run teams (kickoff and punt coverage and return) where he's recorded seven stops.
Senior Dan Fox, 6'3" 240 pounds (2) AND
Senior Carlo Calabrese, 6'1 255 pounds (2)
Notes: Fox generally starts with Calabrese offering ample time in relief. Fox is tied for third on the team with 38 tackles while Calabrese is sixth with 32. Fox's pass defended last week in Norman led to classmate Manti Te'o's interception and kicker Kyle Brindza's subsequent clinching field goal.
Junior Bennett Jackson, 6'0" 185 pounds (2)
Sophomore Jalen Brown, 6'1" 199 pounds (4)
Notes: Jackson ranks behind Te'o for the second on the team in interceptions (4) and passes defended (5), and is tied for third with 38 stops. Brown has played sparingly though appeared in Jackson's stead briefly against Brigham Young when the former left the field due to a neck injury.
Freshman Keivarae Russell, 5'11" 182 pounds (4/5)
Sophomore Josh Atkinson, 5'11" 185 pounds (3)
Notes: Russell is tied with Fox and Jackson for third on the team in tackles (38), including two for lost yardage. Russell posted a career-best 9 tackles last week against Oklahoma. Atkinson has appeared sparingly since September, the highlight a QB pressure that led to a sack of quarterback Andrew Maxwell in East Lansing, a 20-3 win over Michigan State.
Senior Zeke Motta, 6'2" 215 pounds (1)
Freshman Nicky Baratti, 6'1" 206 pounds (4/5)
Notes: Motta was named this week a Thorpe Award semi-finalist, the honor presented annually to the nation's best defensive back. He was not on the pre-season watch list. Baratti secured an end zone interception in the first competitive appearance from scrimmage of his career, taking away a potential score from Michigan in Week Four. He's played mostly on special teams (kick coverage and return) since.
Sophomore Matthias Farley, 5'11" 200 pounds (4)
Senior Chris Salvi, 5'10" 190 pounds (1)
Notes: Farley has started six of eight games this season, the first at Dog linebacker vs. Navy's triple option, the last five at safety in place of injured 5th-year safety Jamoris Slaughter, out for the season since the win at Michigan State with a ruptured Achilles.
A former walk-on who was awarded a scholarship during Winter conditioning, Salvi is a member of the team's kickoff and punt coverage and return teams.
Nickel Defense Interior defensive linemen rotate among Nix, Lewis-Moore, Springmann, and Tuitt while the edge rushers include Tuitt, Shembo, Williams, and Day.
The team's linebackers are generally Spond, Fox, and Williams with Te'o never leaving the field. The team's official nickel defender (fifth defensive back) is freshman cornerback Elijah Shumate, who has broken up three passes in his limited role. Shumate appeared on five snaps last week in Norman while Williams played 17 in a nickel role in addition to his occasional rotation duty at outside linebacker.
The Irish have not shown a Dime package (six defensive backs) since Slaughter was lost to injury in Week Three at Michigan State.
Said Kelly of the nickel defense prior to last week's game:
"I've been the first one to gloat on Danny (Spond) and his play. But we'd like to have (Jamoris) Slaughter so that we'd be in a lot more nickel and dime. It's one of those things where (Spond's) done a really good job, but if we had our way, we'd be in nickel and dime situations. We're trying to groom some young guys to get to that level where we can take Danny off the field. No disrespect to Danny, but we think even in this game, if we can get a nickel…we can't even think about dime. So it's kind of a Catch 22."
Slaughter has applied for a rare sixth season of eligibility for 2013.