Associated Press photo by Mark J. Terrill Notre Dame defensive lineman Sheldon Day looks on before playing USC last month.

NASHVILLE, Tenn. — Sheldon Day was more than ready to join D-Line U. Problem is, D-Line U was on a break.

The Notre Dame defensive tackle knew all about the likes of Kyle Williams, Glenn Dorsey, Michael Brockers and the list that goes on and on for the number of standout defensive linemen LSU has produced. The Indianapolis native wanted to add his name to that long lineage.

Then his visit — or lack thereof — happened.

“I was going to try and take a trip down there, but they were on spring break or some type of break when I went down there for a visit, so I really didn’t get to go over there. I went down to Auburn instead of LSU,” the junior said.

An exciting moment he recalled, Day said he was the first person from his high school, Warren Central, to be offered by LSU.

“If I was going to go SEC, it was definitely going to be LSU,” the 6-2, 285-pounder said. “But I feel like me not being able to go over and visit the campus and things like that kind of hurt them.”

Instead, he stayed in state and went north to South Bend to play for the Irish, where he has started 18 games in three seasons, the last two beset by injuries. He is slated to make start No. 18 when Notre Dame takes on LSU in the Music City Bowl.

He will not be at 100 percent, nor will he likely play 100 percent of the defensive snaps in Tuesday’s game. Day sprained his MCL and missed the final two games during Notre Dame’s four-game slide heading into the game.

“We’d like him to play every play. We don’t think that’s realistic,” coach Brian Kelly said. “If we could get between 40-50 plays, I think we’d be ecstatic.”

When he is in there, he is the anchor of the defensive line that Kelly leans on. Day has 38 tackles, 7.5 for loss, and a sack this season, giving him 94 tackles, 16.5 for loss, and 3.5 sacks in his first three seasons.

He has to be the anchor as running mates Stephon Tuitt and Louis Nix left early for the NFL after last season — a prospect Day and his family are currently discussing as well — and tackle Jarron Jones was saw his season end on Nov. 22 after suffering a Lisfranc injury.

Day, who was on the Outland Trophy watchlist this season and the only returning starter on the Irish defensive line, has seen the team transition from a 3-4 to a 4-3 defense as Brian VanGorder took over for Bob Diaco as defensive coordinator.

“I feel like the transition was smooth for me, especially because I played three-technique in the old defense,” he said. “It was definitely good transition.”

And the transition has moved him into a role that LSU has become a factory for the NFL — defensive tackle.

“Inside, it’s really the trenches and it’s banging all the time,” Day said. “Being out on the end, you have more space and you can kind of be more athletic. On the inside, it’s a grind. It’s a grown man’s world.”

Grown men is all the young and depleted Notre Dame defense has heard about in advance of the bowl game. How can the Irish possibly line up or even last with the power run game and big bodies to execute said game that LSU will present?

“We exert our force early and make them know that we’re ready to play anywhere, anytime,” Day said.

Anywhere, anytime. The irony of those two words for a player who will now line up across from the D-Line U he was so eager to join.

“LSU definitely has some tradition with D-line. We’re definitely trying to get that going here,” Day said.