Brady Quinn's health is a given. No matter how limitless head coach Charlie Weis' offensive wizardry appears, the Irish will not be able to overcome the Heisman Trophy candidate's absence and win the whole thing.
Along with Quinn, there are six other players, if anything happened to them, would make things very difficult for Notre Dame to make an appearance in the Fiesta Bowl on Jan. 8.
Tom Zbikowski: The intimidator of the defense, if Zbikowski went down, there would be a huge drop off from the next guy. He is also by the far the Irish's top special teams threat.
The opposing quarterback always has to locate No. 9 on Notre Dame's defense before snapping the ball, just ask Tennessee and BYU.
Against the Vols, Zbikowski returned an interception for a 33-yard touchdown. In that same game, he made nine tackles including a quarterback sack, and returned a punt 78 yards for another score in a 41-21 victory.
The week before, Zbikowski picked off a pass and ran 83 yards for a touchdown against BYU. Then there was the 60-yard punt return against USC that went for a score.
A stat-sheet filler, Zbikowski's shoes would be awfully big to fill. Something sophomore Ray Herring would be asked to do.
Jeff Samardzija or Rhema McKnight: The Irish were able to overcome McKnight's loss last season because of the emergence of Samardzija and the resurrection of Maurice Stovall. An injury to either one of these guys in 2006 would be very damaging.
Samardzija, a 2005 consensus All-American and maybe the best receiver in the nation, and McKnight, ND's leading receiver in 2003 and 2004 make Quinn better. Superb route runners with great hands, both can make highlight type catches. Samardzija's ridiculous one-handed diving grab against Purdue was one of the best plays of 2005.
With both Samardzija and McKnight on the field, the Irish passing attack is very difficult to defend. If one of those two guys weren't around, the replacement whether it would be David Grimes or Chase Anastasio, wouldn't demand nearly as much attention from the defense before and after the ball is snapped.
Victor Abiamiri: The Irish struggled in getting to the opposing quarterback a season ago. It could be a lot rougher without by far the team's best pass rusher.
The focal point on the defensive line, Abiamiri still had a team-high eight sacks included in his 15 tackles for loss. The next sack Abiamiri makes (ironically numer 12 of his career) will move the senior into Notre Dame's all-time top 10.
With Abiamiri lining up, like Samardzija and McKnight, the senior has to be accounted for by two players. Guys like defensive tackles Trevor Laws and Derek Landri and ends Ronald Talley and Chris Frome will have an easier path to the quarterback because of Abiamiri's presence.
Ryan Harris: It's good to know the 6-foot-5, 292-pound left tackle will be 100 percent when the Irish take the field for the opener Sept. 2, at Georgia Tech.
One of the best offensive linemen in the country, Harris gives Quinn the confidence that his back side is covered on every play. Quinn is able to hold onto the ball a half second longer and feel comfortable with the three-year starter Harris protecting him.
This is not a position where you want a lack of experience. If Harris were to be out, freshman Sam Young or fifth-year senior and career reserve Brian Mattes would have to step in. Harris goes into this season with a streak of 32 consecutive starts.
Maurice Crum Jr.: The quarterback of the defense and the only returning linebacker with significant experience, if Crum were to be out of action, it would be the team's most crushing loss besides Quinn.
Crum is healthy after missing the entire spring recovering from injury. The junior has moved from strongside linebacker to the middle. He also has the ability to play weakside if necessary. Nobody else has that kind of versatility.
The 6-foot, 220-pound Crum will be the guy making sure everyone on defense is lined up properly. He will also be the guy in position to make the most plays.
The linebackers are the biggest question mark on the team, and without Crum, they would be by far the most inexperienced. Freshman Toryn Smith would have to step up and assume most of Crum's responsibilities, a very tall task. Zbikowski would probably inherit some of Crum's roles as well.
Certainly, injuries to leading-rusher Darius Walker, leading-tackler Ambrose Wooden, center John Sullivan or any other starter for that matter would be damaging, but the situation could be MacGyvered. Linebacker Travis Thomas would return to running back and senior Joe Brockington would be promoted to starting weakside linebacker. If something were to happen to Wooden, there are several talented options at cornerback. Three-year starter Bob Morton could slide over from guard to center in Sullivan's absence, with Mattes moving into Morton's old role.
There is a good answer to replace everybody with the exception of the six guys named above. And of course Quinn.