The 32-year-old hasn't played an NFL game all season and participated in his first practice with the team on Tuesday.
Jackson was the 24th overall pick of the St. Louis Rams in the 2004 draft. In nine seasons in St. Louis, he became the franchise's leading rusher with 10,138 yards and had 56 rushing touchdowns, two behind Marshall Faulk for most in Rams' history.
In 2013, Jackson signed a multi-year deal with the Atlanta Falcons. Jackson had 1,250 yards and 12 touchdowns over two seasons in Atlanta before he was released on Feb. 25.
Jackson is 18th on the NFL's rushing list with 11,388 yards and has 68 rushing touchdowns.
In a corresponding roster move, New England released defensive lineman Ishmaa'ily Kitchen.
Kitchen, who had a brief stint with the Detroit Lions earlier this season, was signed to the Patriots' practice squad on Dec. 16.
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