Seahawks linebackers could be involved in some of the fiercest position battles when training camp arrives.

For now, though, as Seattle enters its second week of Organized Team Activities (OTAs), it’s a position group more notable for those who are missing.

The latest addition to the list of walking wounded is Bruce Irvin, who the team said had hip surgery Monday. Coach Pete Carroll did not talk to the media after the workout and the team did not offer an official prognosis.

Irvin, though, took to Twitter to say he will be back by training camp in late July.

“Didn’t want this to get out but I’m fine! Will b back by training camp!’’

The Seahawks’ first-round draft choice in 2012 later added via Twitter that he would not have had the surgery if he was going to miss any games. “I decided to proceed because I could b back soon,” he wrote.

Already missing OTAs is Super Bowl MVP Malcolm Smith, out after recent ankle surgery. Smith and Irvin are likely to vie for the starting strongside linebacker spot. Regardless of who officially wins that battle, though, each will have a significant role this season. Irvin also will play some defensive end, specifically the LEO rush end spot, while Smith also can play weakside linebacker.

Also limited of late has been fourth-round choice Kevin Pierre-Louis, hobbled with a groin issue since rookie minicamp.

Also out Monday was veteran O’Brien Schofield, who as Irvin also plays defensive end but also can play some strongside linebacker.

The absences Monday had fourth-year vet Mike Morgan often lining up with the first unit on defense at linebacker alongside starting middle linebacker Bobby Wagner and weakside linebacker K.J. Wright.

Wagner said the linebackers who are out there are off to a good start.

“I think we are really focusing on making sure we are running (at) the ball and really showing our effort right now trying to perfect everything and pick up where we left off last season,’’ Wagner said.