After a lengthy rehab from knee injuries, Raiders LB Aaron Curry has been activated. (US Presswire)

The Raiders added linebacker Aaron Curry to their active roster Tuesday from the PUP list, ending his long struggle to overcome knee injuries and return to action.

To make room for Curry on their 53-man roster, the Raiders waived outside linebacker Vic So'oto, who had been primarily a special teams player.

In a training camp interview, Curry said his knees began bothering him during OTAs, but he tried to keep practicing. That only made the problem worse.

When camp opened, Curry was placed on the active/physically unable to perform list. Then on Aug. 28 he was moved to reserve PUP.

Curry practiced for the first time on Oct. 17. At that point, the Raiders had a 21-day window to either activate Curry, waive him or place him on injured reserve.

During the past three weeks, Curry has been working his way back into football shape and getting practice time at all three linebacker spots -- strong-side, weak-side and middle. He has also had some work on special teams, coach Dennis Allen said.

Seattle drafted Curry in 2009 out of Wake Forest, using the No. 4 overall pick. But he never lived up to that high billing, and the Seahawks traded him to Oakland last season on Oct. 14, 2011, for a seventh-round draft pick in 2012 and a conditional draft choice in 2013.

Curry appeared in 11 games and started nine at weak-side linebacker for the Raiders last season. He made 46 tackles.

Before getting injured, Curry was expected to open training camp as the starting weak-side linebacker. That job went to rookie Miles Burris, a fourth-round draft pick from San Diego State. For the past four weeks, Burris has been an every-down player, taking over starting middle linebacker Rolando McClain's role in the nickel.

Follow Raiders reporter Eric Gilmore on Twitter @CBSRaiders.