SANTA CLARA, Calif. » With their 2009 sack leader missing in action this spring, the San Francisco 49ers have three young veterans making the most of the opportunity presented by his absence.

Ahmad Brooks, Parys Haralson and newcomer Travis LaBoy are picking up the slack at outside linebacker for incumbent starter Manny Lawson, who’s in the final year of his contract with the 49ers and has yet to take part in the team’s offseason program.

No Lawson means more practice snaps for Brooks and LaBoy and increased time for Haralson at left outside linebacker, where Lawson normally starts in San Francisco’s 3-4 defensive set.

"It’s giving them an opportunity to get out there and get coached on the go," 49ers coach Mike Singletary said yesterday. "All of those young guys have really benefited, because they all wouldn’t normally be getting as many reps as they are getting right now."

Haralson lined up on the left side with the first unit and Brooks was the starter at right outside linebacker yesterday when the 49ers completed a week of organized team activities.

Though most of the roster has participated throughout the spring, all of San Francisco’s offseason workouts so far have been voluntary. Lawson, the team’s 2006 first-round draft pick, is reportedly unhappy he has not been given a contract extension and is one of a handful of veterans who has yet to make an appearance.

That comes at a bad time for a team that’s intent on improving its pass rush to lift a rising defense to the next level. Lawson led the team with a career-high 6.5 sacks last season, but the 49ers are looking for even more production from the outside linebacker positions, which are the key pass-rushing roles in the team’s 3-4 scheme.

The 49ers signed Brooks to a two-year, $4.23 million deal and brought in the free-agent LaBoy with a one-year, $1.6 million deal during the offseason.

Brooks pretty much took Lawson’s job at left outside linebacker during third-down rushing situations over the final six games last season, when he emerged as a force for the first time in his four-year NFL career. Brooks ranked second in the league over the final five games last season with five sacks. He finished the year with a career-high six sacks.

After not playing a single down in 2008, his first season with the 49ers, Brooks now is primed to become an integral part of the team’s 2010 defense.

"I’m more comfortable with everybody and everything around me now," said Brooks. "I’ve had some setbacks, but I feel this is my time to just go out and shine and be a dominant player that I know I can be in the NFL. Manny’s still the starter right now, but him not being here helps me out and gives me more of a chance and more reps to perfect my craft."

LaBoy had six or more sacks in two of his final three seasons with the Tennessee Titans before the Arizona Cardinals signed him in 2008. He had four sacks in his first four games with the Cardinals, but a foot injury that required reconstructive surgery derailed his career in Arizona, and he did not play in 2009 after being released.

Now he’s returning to the area where he was raised and is getting a fresh start with the team he grew up rooting for as a youngster.

"I’m still knocking off some rust, getting back in the flow of football, but every day I get a little better," said LaBoy, who has played primarily defensive end so far in his NFL career and was All-WAC at the position at Hawaii.