Mathews is first of four possible camp no-shows for Chargers

The San Diego Chargers opened training camp Monday without rookie running back Ryan Mathews, the heir apparent to LaDainian Tomlinson.

It's a theme that should be repeated Thursday, when the veteran reporting date is expected to pass with no sign of Pro Bowl wide receiver Vincent Jackson, left tackle Marcus McNeill and perhaps outside linebacker Shawne Merriman.

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Mathews, though, is expected to be in pads much sooner than Jackson and McNeill, who likely will miss training camp and probably the first 10 games of the season because they're unhappy that they haven't been signed to long-term deals.

The Chargers rarely have their top draft pick signed by the time rookies report, and Mathews is no exception.

The 12th pick overall out of Fresno State, Mathews is San Diego's only draft pick who hasn't signed.

"I like the young guys to be here," Chargers coach Norv Turner said after the opening practice. "I'm anxious for Ryan to get here. He knows it's important to get here. There were three or four things that came up today that I would have liked to have him see. So yeah, he's missing things. Those things he can make up, also."

Asked for an update on contract negotiations with Mathews, Turner said: "You've got the wrong guy. I'm like you. Just let me know when it's done."

Mathews, his agent and Chargers general manager A.J. Smith didn't return calls from The Associated Press seeking comment.

Rookies and selected veterans will practice through Thursday, when the rest of the veterans are due to report. The first full-squad practice will be Friday for a team that went 13-3 and won its fourth consecutive AFC West title last year before imploding in an embarrassing home playoff loss to the New York Jets.

Jackson, who has back-to-back 1,000-yard receiving seasons, and McNeill, who protected quarterback Philip Rivers' blind side, are upset at being tendered one-year contracts as restricted free agents, at just more than $3 million each. When they didn't sign the offers by June 15, the Chargers were entitled to offer them their same salaries as 2009, resulting in a loss of about $2.5 million each.

Merriman hasn't signed his tender for $3.269 million, but he was due a 10 percent raise anyway, which would put his 2010 pay at approximately the tender amount. Sources told *The San Diego Union-Tribune* on Saturday that Merriman and the team are in the early stages of discussing the possibility of the linebacker signing his tender and joining the team.

Merriman said in an e-mail that he had "no idea yet" when he'd report. "I'm just taking it one day at a time," he said.

Being without Jackson and McNeill could have a significant impact on a team that has shifted from a power running game to being a pass-happy offense behind Rivers, who last summer received a contract extension worth nearly $93 million.

"I think everybody in here would love that they would be here on Friday," Rivers said. "At the same time, nobody's developing anything toward them.

"There's no denying the players they are and that we're better with them, but at the same time, let's worry about what we can control and go out here and let guys step up and play," Rivers added. "All that means is other guys are getting opportunities that they haven't gotten in the past."

Legedu Naanee stands to gain the most by Jackson's absence.

"I feel like this is a huge opportunity for me," said Naanee, who's entering his fourth NFL season. "I'm excited about it, I feel like I'm ready for it. I'm just going to come in here and play and hopefully make the decision tough on them when Vincent comes back."

Naanee's best season was 2009, when he had 24 catches for 242 yards and two touchdowns. He would start opposite Malcom Floyd, who was San Diego's third-leading receiver last year behind Pro Bowl tight end Antonio Gates and Jackson, with 45 catches for 776 yards and one touchdown.

"It hasn't really been a huge thing in the locker room," Naanee said of the absence of Jackson and McNeill. "We're just getting ready to play, and hopefully they're with us, and if they're not, we have to play anyway, so we're just getting ourselves ready."

To fill in for McNeill this season, the Chargers have signed 35-year-old Tra Thomas, a three-time Pro Bowl pick. Second-year pro Brandyn Dombrowski, who played right guard and right tackle last year, also can play left tackle.

The Associated Press contributed to this report.