The team announced the signing Thursday.
The 27-year-old player, who is entering his fourth NFL season, spent part of last season with the New Orleans Saints before suffering a biceps injury. His contract with New Orleans expired following the season. In 2007, Stanley started six of 14 games played for the Atlanta Falcons and finished with 35 tackles and two fumble recoveries.
Stanley had previously signed with the Jaguars in September 2006. He made four tackles in three games but was waived after two months on the team.
The Jaguars on Thursday also waived defensive tackle George Hypolite, an undrafted rookie from Colorado.