Greg Gilmore is here to stay, he says.

Oh, what’s that — many expect him to lose his starting job as LSU’s nose tackle? He shrugs that off.

Oh, he’s 50 pounds lighter than his competitor? He doesn't care.

Oh, he’s battling with the former No. 1-rated defensive tackle in junior college? He's not afraid.

“I like that,” the redshirt junior said Monday. “I like being the underdog.”

Gilmore is jostling with Travonte Valentine for the Tigers’ starting nose tackle position, a key spot in new coordinator Dave Aranda’s 3-4 defense. Gilmore said Valentine is, sometimes, receiving “half the No. 1 reps” during practice, as the two rotate.

Less than two weeks before the season-opening duel against Wisconsin, LSU’s starting nose tackle appears to be an open, rotating spot. It’s likely to remain that way during the season, too, a position where not just one player plays the entirety of the game.

The battle between Gilmore and Valentine, though, is one of the most competitive fights on a team that returns all but five starters. Up for grabs is a critical position, too.

After all, the player is literally and figuratively at the center of LSU’s defense, a key cog who must plug holes and handle double-teams. The 356-pound Valentine excels at the latter, players and coach Les Miles have said. Even the 308-pound Gilmore admits to being at a disadvantage when it comes to taking on multiple blockers.

“I can’t take triple teams like that. I have to use straight technique while I’m in there. I’ve got to be technique sound, be able to pass rush and move and bend. He’s in there clogging the hole, driving people back,” Gilmore said. “He takes up double-teams and eats double-teams up. It’s not like he’s taking double-teams and just sitting there, man. He’s pushing them back.”

Valentine, dismissed from LSU last summer before his return two weeks ago, has not been made available to reporters. But his status on the team is becoming quite clear: He should play significantly.

He isn’t as far along as some players, though. Valentine, a redshirt sophomore, joined the team on the seventh day of preseason camp and became eligible for the season Monday. He missed summer workouts and spring practice — both key times in which Aranda installed his new scheme.

Valentine is playing catchup, and Gilmore, his competitor, is helping out.

“(When) we teach him technique, he’s going to be unstoppable. He learns 10 percent technique, he’s going to be real good,” Gilmore said. “After practice, we get on the side and work on our plays. He has to learn the defense, learn the concepts.”

Don’t forget about Gilmore, though. He appears to be at the top of the depth chart — for now. The North Carolina native signed as a five-star prospect by Scout.com, redshirted as a freshman in 2013 and played in just six games in 2014. Last season, he evolved into a rotating reserve at tackle, seeing three to five series a game.

He’s banking on more playing time this year in that central position. Defensive line coach Ed Orgeron admitted in the spring that LSU had “work to do” to find a nose tackle who can fulfill duties — like handling a double-team and dominating the center in a potential one-on-one matchup.

“You have to be able to do some things. It’s a little different from the 4-3. It’s taking some time to adjust,” Orgeron said then. “You line head up on the guy. You line up right dead in the middle instead of the 4-3 (lining up) on the edge. You’ve got to be able to knock back the center.”

You've got to "command double-teams" too, a phrase often tossed around by LSU defensive linemen regarding Aranda's new system. It’s one of the reasons LSU, midway through spring practice, swapped Davon Godchaux and Christian LaCouture, moving Godchaux from end to nose and LaCouture from nose to end.

The nose tackle in a 3-4 must be a dominant player whom the offense feels it must block using two — not just one — offensive linemen, Aranda said in spring. That frees up the linebackers to make plays, an essential part of this system, said Pete Jenkins, a long-time defensive line coach-turned-consultant who now lives in Baton Rouge.

"I was always lucky to have a good nose," Jenkins said. "I learned this from coach (Bear) Bryant. You need a good center on offense and a good nose on defense. That ole saying, ‘If you’re strong right up the middle, you’re going to be pretty good.’ That goes for almost every sport."

Gilmore knows all of this, of course, but how do you become a good nose? How do you practice commanding double-teams?

“You’ve got to put yourself in the hole, man,” Gilmore said, referring to the gap between a center and guard. “You’ve got to split the guys, man. You really have to be the anchor. It’s really a mindset.”

Gilmore spent the summer watching some of the better nose tackles in the game, specifically Justin “Jelly” Ellis, a 6-2, 335-pounder who plays for the Raiders. Ellis is a former Louisiana Tech standout and Monroe native who’s worked with Jenkins, a close friend to Orgeron who provided consultant help with Aranda earlier this year.

“He has great technique, great hands,” Gilmore said of Ellis. “I like to watch his film. I’ve seen videos of him working with Pete. I kind of mimic that.”

There’s somebody breathing down his neck, though — a hulking, hyped-up Miami native whom coaches and players are raving about.

“I like somebody that wants to fight for my spot and wants to push me,” Gilmore said. “I want to play harder, want to learn from him too.”

Follow Ross Dellenger on Twitter, @RossDellenger.