Lloyd began his career in San Francisco, joining the Niners as a fourth-round pick in the 2003 Draft and spending three seasons with the team before his departure following the 2005 campaign.
The 32-year-old has since spent time with the Washington Redskins, Chicago Bears, Denver Broncos, St Louis Rams and, most recently, the New England Patriots.
He recorded 74 catches for 911 yards and four touchdowns in 2012 but did not play in the NFL last season. His best year came in 2010, when he led the Broncos with 1,448 receiving yards and was voted to the Pro Bowl.
The journeyman joins the 49ers on a one-year contract and is expected to compete to be the number three receiver as the team are likely to add more players in his position in the Draft.