Lucas (knee) was activated from the reserve/PUP list Wednesday, John Boyle of the Seahawks' official site reports.
Lucas' 21-day window to practice with the team was coming to a close, so if Seattle didn't move him to the active roster, he'd be lost for the remainder of the season. However, the 26-year-old has been practicing on a limited basis for the last couple of weeks and, according to head coach Mike McDonald, Lucas has looked "really good" and it's a "realistic expectation at this point," for him to play Sunday against the 49ers, as reported by Brady Henderson of ESPN.com.