NAPA, Calif. (AP) — On Oakland's opening day of training camp practice, there was more focus on who wasn't on the field than who was playing for the Raiders.

Pro Bowl left tackle Donald Penn was a camp holdout Saturday because of a contract dispute and five other players, including first-round pick Gareon Conley, were placed on injured lists and aren't able to practice.

Coach Jack Del Rio said he found out Friday morning that Penn wouldn't be reporting to camp as he hopes to get an improved contract.

"My thought on that is we love Donald," Del Rio said. "He's a good Raider, good player. What's important for us is to focus on the work here, on the guys that are here. That's how we're going to approach it. There's a business side. There's a time for pay and a time for play. Once we get to camp my focus has to be for our team on just growing and going forward. Obviously we love Donald and would love to have him and hopefully that gets resolved."

Penn is entering the final year of an $11.9 million, two-year contract. He is scheduled to earn $5.8 million in base salary this season with another $1.3 million in incentives and bonuses.

Penn is coming off his second Pro Bowl after being part of an offensive line that allowed a league-low 18 sacks in 2017.

Penn allowed only one sack in 2016, during Week 16 against Indianapolis, but it was a pivotal one: Quarterback Derek Carr suffered a season-ending broken right fibula on the play.

"I never put my hand in another man's pocket," Carr said. "I stay far away from that. Everyone here from top to bottom loves him. He knows that. But we're focused on who's here and getting better. He knows how everybody feels about him but I never step into another man's situation like that."

With Penn absent, free-agent acquisition Marshall Newhouse lined up at left tackle. Newhouse is the leading contender to get the right tackle spot after Austin Howard was released earlier this week. Second-year player Vadal Alexander worked on the right side.

"This can be valuable time for a guy maybe to get a few more reps than he would have because of the current situation," Del Rio said. "We look to utilize that, turn it into a positive and take that time develop these guys and bring them along maybe a little bit quicker."

Conley was placed on the physically unable to perform list a day after signing his rookie deal. Conley had an undisclosed injury late in the offseason program and is still not healthy enough to practice.

Offensive lineman Jon Feliciano was also placed on the PUP list after hurting his knee during organized team activities, along with defensive tackle Jihad Ward, who is recovering from offseason foot surgery.

Linebacker Bruce Irvin and defensive lineman Mario Edwards Jr. are on the non-football injury list after getting hurt since the end of training camp in June.

Edwards and Feliciano were training on the side during practice and Irvin came out to watch the end of practice.

"You don't understand how itchy he was on the sideline looking at us today," teammate Khalil Mack said. "I told him, 'Just chill out.' He'll be good. He'll be out there in a few days."

This is the start of what could be an odd season for the Raiders, who ended a 13-year playoff drought by winning 12 games last season and come into 2017 with high expectations to challenge New England in the AFC.

But the team also announced this offseason plans to move to Las Vegas in 2020, creating a situation of being a lame duck in Oakland. The team still managed to sell out the Coliseum for this season as Oakland fans aren't ready to give up on the team just yet.

Del Rio is trying his best to shield his players from any kind of distraction.

"We're about investing in the here and now," he said. "Obviously there are people in our organization that have to work on things that pertain to that. That's not where we are. Players and coaches are locked in. Our focus is on being as good as we can be here and now. Right now we're in Napa. We need to get our work done here in Napa and we'll be the Oakland Raiders this year."

NOTES: The Raiders claimed RB George Atkinson III off waivers from Cleveland. Atkinson spent parts of three seasons with the Raiders before being picked up by Cleveland last September. ... The Raiders had about 100 former players on hand at practice as part of alumni weekend.

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