The 49ers signed Lucas to a one-year deal Friday, Mike Garafolo of NFL Network reports.
The Lions elevated Lucas to their active roster Saturday, Mike Garafolo of NFL Network reports.
Lucas participated in OTAs on Monday and appears to have recovered from his hamstring injury.
The Lions designated Lucas (hamstring) to return from injured reserve Wednesday, Colton Pouncy of The Athletic reports.
Detroit placed Lucas (hamstring) on its injured reserve list Saturday.
Lucas (hamstring) is out for Sunday's game against the Vikings.