Jared Veldheer tears triceps

NAPA, Calif. -- Oakland Raiders starting left tackle Jared Veldheer has only a partially torn left triceps, and doctors believe he will be available for much of the season, a source familiar with the injury told ESPN NFL Insider Adam Schefter Wednesday.

The Raiders had feared Veldheer would need surgery. That may not be necessary, the source said, but that decision will come after Veldheer gets a second opinion, which is expected to come within the next 24 hours, the source said.

The injury is considered a lesser version of what Baltimore's Ray Lewis and San Francisco's Justin Smith both dealt with last season.

Veldheer has been bothered by the triceps throughout training camp and had a second MRI performed Tuesday when it did not feel any better.

"It's a disappointment for all of us," coach Dennis Allen said. "But, again, we're going to play 16 games this year. The teams that are able to push through those things mentally, those are the teams that have success. Everybody has injuries. That's one we'll just have to deal with."

Veldheer's injury gives Alex Barron, a former first-round pick by the St. Louis Rams who has not played a game in the NFL since 2010, a shot at a starting role.

"Of course, it's an opportunity," Barron said. "First and foremost, it's an opportunity to be here, period. It's another opportunity, obviously, to go up on the chart and help the team as best I can."

Barron was drafted 19th overall in 2005 out of Florida State but struggled for almost his entire five seasons in St. Louis. He started 74 games and played both left and right tackle but was plagued by penalties and poor blocking.

He committed 43 false-start penalties -- including 13 in 2006 -- and 13 holding penalties while allowing 33 sacks, according to game tracking from STATS LLC.

He was traded to Dallas in 2010 and played 11 games with the Cowboys. But Barron hasn't played since, spending a little time with New Orleans and Seattle without ever getting into a game.

"I think Alex has been playing very well," quarterback Matt Flynn said. "I was with him in camp last year in Seattle. He seems like a different guy here. He's playing well, playing aggressive and really coming into his own."

Veldheer was perhaps Oakland's most indispensable player, given his talent and the importance of the position he plays. He has started the past 42 games at left tackle, missing only one offensive snap in that time.

A third-round pick out of Hillsdale College in 2010, Veldheer was an emerging left tackle who was counted on as a major piece of the Raiders' rebuilding project. Veldheer was rated by Pro Football Focus as the eighth-best pass-blocking left tackle in the NFL last season. He has been responsible for just four sacks in each of the past two seasons, according to STATS LLC.

"It's a real big blow," right tackle Khalif Barnes said. "Jared's a big part of our line. He's a big guy. He comes to work every day, you never hear him complaining, just tries to go in, get the job done, he just tries to perfect his craft every day at practice. He's a good part of our team, a good leader for our team."

The Raiders have been hampered by injuries on the line throughout camp. Right guard Mike Brisiel has been out all week as he struggles to recover from offseason ankle surgery. Lucas Nix, who is batting with Tony Bergstrom for the left guard spot, also has missed significant time in camp with an undisclosed injury. Second-round pick Menelik Watson has not practiced all camp with a calf injury.

With Oakland changing blocking schemes from a zone system to more power blocking this season, the lack of continuity on the line is a concern.

"It definitely hurts," center Stefen Wisniewski said. "We've had a couple of left guards in there, a couple of right guards in there, and now we're working with a new left tackle. But I think we're all communicating really well. I think it's just a matter of getting your footwork right, and getting some of those combination blocks right."

Information from The Associated Press was used in this report.