The Patriots did not disclose the terms of the deal with the 29-year-old Jordan, which was announced Saturday.
Oakland signed Jordan in 2005, but he never developed into the elite back the team envisioned. He had 19 carries in the final nine games last season.
His stock dropped further after Oakland selected running back Darren McFadden with the fourth overall pick of April's draft.
Jordan has rushed for 3,285 yards and 24 touchdowns in seven seasons with Oakland and the New York Jets.
His best season was 2005 with Oakland, when he rushed for 1,025 yards and nine touchdowns and had 563 yards receiving with two touchdowns.