Fletcher Cox pulled Destiny Vaeao aside before training camp and told the Eagles' third-year defensive tackle about the opportunity available. The Eagles open the preseason next week and the regular season in five weeks, and their defensive tackle rotation remains one of the biggest questions.

Tim Jernigan, who is supposed to be the starting defensive tackle next to Cox, has a back injury that sidelined him throughout the offseason and could stretch into the season. Jernigan hasn't even attended practices, with the training staff sequestering him indoors to rehab and avoid any chance of an accident.

The team has been vague about  Jernigan's injury, but when coach Doug Pederson was asked if he's still counting on Jernigan, his answer was: "I think so." It's possible Jernigan could remain on the non-football-injury list to start the regular season, which would keep him out of the lineup at least until after Week 6.

Last season Jernigan took 49 percent of the snaps. Beau Allen, who left in free agency, took 41 percent of the snaps. So to start this season, the Eagles might have major changes at defensive tackle. And though veteran Haloti Ngata is expected to play a key role, the Eagles have spent the last week preparing Vaeao to line up next to Cox, and might even need to look down the depth chart at players such as Elijah Qualls or Aziz Shittu.

"I'm not worried one bit," Cox said. "Those guys, they can play ball. Destiny can play, Haloti can play. Whoever fits that position until Timmy comes back."

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Start with Ngata. The 34-year-old, five-time Pro Bowler was signed this offseason to join the Eagles' defensive line rotation – ostensibly to take Allen's spot as the third tackle. He comes to the Eagles after playing only five games with the Lions last season. He has not played more than 60 percent of the defensive snaps in a season since 2013, and he has not played a full 16-game season since 2011.

He has enjoyed a strong career, but he would seem to fit more as a part-time player at this point. Defensive coordinator Jim Schwartz has purposely integrated Ngata slowly into the fold this summer by working him mostly with the second-team defense, and Pederson even gave the veteran a day off Thursday.

"We'll have to see," Ngata said about taking a bigger role with Jernigan out. "[Vaeao] is doing such a great job right now. I'm learning a lot from [Vaeao] and him being in front of me. We're going to have a good rotation and strong defensive front."

That's polite of Ngata to say, considering he's 10 years older than Vaeao, and Vaeao raved about how much he has learned from Ngata in their short time together. But it's true that Vaeao has more experience in this defense.

He made the Eagles in 2016 as an undrafted player and was with the team again last season, although a wrist injury slowed his on-field progress. He was inactive for five regular-season games and two postseason games, including the Super Bowl. After spending his first two years mostly as the fourth defensive tackle, he has been made aware that he has a  chance to take on a bigger role this season – at least when Jernigan is out.

"That will be decided in training camp and the preseason games," Schwartz said. "I liked where he was coming out of training camp last year. Unfortunately, he got hurt in the first game, and then he had to play with that cast on the rest of the year. So, this is a big year for him, just sort of putting it all together. … He's a little bit bigger now, but not overweight. He's just bigger. He's just matured a little bit more."

Vaeao, a soft-spoken American Samoa native, is listed at 6-foot-4 and 299 pounds – comparable to his measured weight at the 2016 combine. He would not divulge how much weight he has added, but he said the bigger frame will help him fight off offensive linemen.

He has spent the last two years developing how he uses his hands as a defensive tackle, which is why the wrist injury made last season difficult. Playing with a cast disrupts how a defensive tackle can engage with offensive linemen, and when it happens during the season, there's little time for a player to adjust.

Vaeao has taken advantage of the increased workload during the last week, and the coaches will be watching him closely during the preseason to determine how much he can help come Sept. 6.

Vaeao doesn't want to act as if  he's arrived, but he's not acting surprised that the coaching staff has put him next to Cox this offseason.

"Everyone is aiming to be a starter in this league," Vaeao said. "I've been ready. Every year, you have to be ready. Because if you're not ready, they're going to kick you out."

The Eagles are not limited to the defensive tackles on the roster. Schwartz likes to move defensive ends inside to tackle on pass-rush downs, as they did with Brandon Graham last season. Michael Bennett could do so this season. So even if the Eagles are undermanned at defensive tackle, they will rely on defensive ends to help.

Of course, it helps to have Cox. And Cox's message to Vaeao can apply to anyone else vying to fill Jernigan's shoes.

"I'm the leader," Cox said. "Just follow me."