Notre Dame Fighting Irish vs BYU Cougars prediction: Without LJ Martin, Bachmeier must run at Notre Dame's wall

The run game loses its hammer

Provo hosts its first top-10 matchup, and BYU arrives without the player who made its offense work. Kalani Sitake confirmed running back LJ Martin won't play against the Irish, and he faces four to six weeks out with a lower-body injury. That hurts a team built on the ground: BYU ranks 2nd of 138 in rushing EPA per play (expected points added on each run) and 8th in line yards per carry, a measure of how far the front pushes defenders back.

The Irish allow 58.3 rushing yards per game, 3rd nationally, and rank 4th in rushing EPA allowed. Journee Tonga, the next man up, ran 8 times for 19 yards against Iowa State. That leaves the burden on Bear Bachmeier, who has 239 rushing yards this season and 109 of them came in the Iowa State win. Notre Dame's defensive line may be thinner too: tackle Jason Onye is questionable with a left ankle injury.

Carr runs a quiet machine

Notre Dame's offense doesn't rely on big plays. It ranks 107th in explosiveness yet 3rd in success rate, the share of plays that keep an offense on schedule, at 53.1%. It finishes too: the Irish score 5.37 points per scoring opportunity, 2nd in the country.

C.J. Carr is the engine. He has 16 touchdown passes against 1 interception at 9.6 yards per attempt, and he threw 10 touchdowns in the last three games alone. BYU's pass defense is sound, 16th in passing EPA allowed, but it gives up 3.25 points per opportunity, 63rd. When Notre Dame gets into scoring range, BYU has bent more than it should. Freshman Jonaz Walton adds a second gear; his 97-yard run capped 181 yards on 13 carries against Stanford.

Havoc against a clean pocket

Here BYU holds its best counter. Notre Dame's havoc rate, the share of plays ending in a tackle for loss, sack, forced fumble, interception or pass breakup, is 22.8%, 3rd nationally. BYU's offensive line allows havoc on just 7.7% of plays, 2nd. If the Cougars keep Bachmeier upright, they can sustain drives; they convert 54.4% of third downs, 7th.

The risk is ball security. Notre Dame forces 2.33 takeaways per game, 3rd, while committing a nation-best 0.17 turnovers per game. Bachmeier's floor is the worry: he went 11 of 24 for 62 yards at TCU. A night like that against this defense ends the competitive part early. Starting cornerback Leonard Moore is questionable with a concussion, which matters if Bachmeier finds rhythm through the air.

Résumés and the number

Notre Dame's 16-game win streak has come against modest company this fall, with an average FBS opponent SP+ of -2.1. The average SP+ of its FBS opponents is -2.1, against 4.4 for BYU's slate.

BYU has covered all five of its games with a line, but it did so as the favourite every time. Now it's a home underdog at +12.5, a number that hasn't moved from the open. The Cougars' wins over TCU (17-10) and Iowa State (24-10) suggest a team comfortable in low-scoring games, and Bachmeier is 17-2 as a starter. Without Martin, though, BYU's path to a slow game is less reliable.

What to watch

• Kick returns: BYU averages 42.0 yards per kick return, 2nd nationally, while Notre Dame allows 24.3, 116th. A short field is BYU's cleanest route to points.
• Early downs for BYU: If Tonga and Bachmeier can't stay ahead of the chains, the Irish pass rush gets its chances.
• Final injury reports: Moore and Onye for Notre Dame, plus BYU's availability report released 90 minutes before kickoff.