With buzz and expectations come issues that sometimes pop out of nowhere. Raiders offensive tackle Donald Penn was a no-show Friday, a surprising holdout as veteran players reported to training camp at the Napa Valley Marriott.

Penn is frustrated at his contract, a year after signing a new two-year, $11.9 million deal. The 34-year-old made the Pro Bowl last season, his third with the team, and only this week told the team of his displeasure, The Chronicle learned. Raiders officials didn’t expect him to not show up for the start of camp.

Penn and his agent didn’t return phone calls, but Penn did talk to former Patriots linebacker Willie McGinest, now an NFL Network analyst, on Friday. McGinest said Penn “wants to be paid in the top 10” of left tackles. Penn’s 2017 salary of $5.95 million ranks 23rd, according to spotrac.com, while the Rams’ Andrew Whitworth is at No. 10 at $11.25 million.

“(Penn) just wants the respect for what he’s done on the field,” McGinest said. “Stop looking at his age; look at his production.”

Penn would appear to have some leverage, as Oakland just gave quarterback Derek Carr a $125 million extension and signed running back Marshawn Lynch, and there is no obvious candidate to step in at left tackle. Then again, the Raiders can fine him up to $40,000 for every day that he misses.

The Raiders’ first practice is Saturday. Head coach Jack Del Rio isn’t available to the media until then.

Scott Strazzante/The Chronicle

Meanwhile, the Raiders signed first-round pick Gareon Conley on Friday evening. The cornerback missed four precamp workouts with the other rookies and quarterbacks in Napa, but the team was never too concerned about him missing the first practice on Saturday.

Conley is under investigation by Cleveland police on rape allegations made in April. He hasn’t been charged, and he said his meeting with the police in May went well.

Back to Penn. Center Rodney Hudson was one of the four players made available Friday, and wasn’t too stressed about Penn’s Day 1 absence.

“We’ve talked throughout the offseason,” Hudson said. “I haven’t quite spoken to him today, but those things are going to work themselves out at some point.”

Penn has never missed a regular-season game in his career, but did miss a chance to play in his first playoff game, after a left knee injury forced him to miss Oakland’s wild-card-game loss to Houston.

Penn only gave up one sack last season, but it was the one that ended Carr’s season (broken leg) in Week 16 against Indianapolis.

Meanwhile, in a non-surprising move, the Raiders released offensive tackle Austin Howard late Thursday night.

Howard, 30, started 39 games for the Raiders over the past three seasons, coming in as a guard before moving back to his more natural tackle position the last two seasons. He was not projected to be in the battle for the starting right tackle job this season, and the team was waiting for him to heal from shoulder surgery before making a move.

Howard gave himself up for the team last season, starting in Week 2 when an ankle injury wasn’t healed because Oakland had two other lineman injured in the season-opener.

“I came to Oakland my first year with a start of 0-10,” Howard posted on Instagram. “Through hard work and dedication we built a team that had more success than it had in years, and thus we turned this group of players into a play-off bound and elite team.

“Starting on this Offensive line for the majority of that time is something that I’ll never forget.”

Howard signed a five-year, $30 million contract as a free agent in 2014, and the team will save $5.5 million on next year’s salary cap by releasing him.

Former Giant Marshall Newhouse is No. 1 on the depth chart at right tackle and will be pushed by second-year player Vadal Alexander. The Raiders also drafted tackles David Sharpe and Jylan Ware this spring.

Vic Tafur is a San Francisco Chronicle staff writer. Email: vtafur@sfchronicle.com Twitter: @VicTafur