Richardson signed a contract with the Seahawks on Saturday, Mike Garafolo of NFL Network reports.
Richardson played four seasons with the Seahawks from 2014-17 but never emerged as a true starting option until his final year, when he posted career highs in receptions (44), receiving yards (703) and touchdowns (six). With Phillip Dorsett (foot) expected to be out for "some time" according to coach Pete Carroll, Richardson offers a unique type of speed behind the likes of DK Metcalf and Tyler Lockett.