On March 12, 2019, the Patriots placed a second-round tender on Gordon, securing his services for the upcoming 2019 season, should he be reinstated by the NFL. Gordon took to Instagram shortly after to thank the team, and reaffirm his commitment to getting back on the field. Two weeks later, during a press conference at the Governors’ meeting in Arizona, NFL Commissioner Roger Goodell was asked about Gordon's status, and said that "the NFL was focused on getting him on the right track, and hopefully back on the field soon". Ultimately, on August 16, 2019, the NFL conditionally reinstated Gordon, thus granting him the opportunity to play Week 1. During Week 1 against the Pittsburgh Steelers, in his first game since Week 13 of the 2018 season, Gordon had three receptions for 73 yards and one touchdown in a 33–3 win. On October 23, 2019, the Patriots placed Gordon on injured reserve with a knee injury. He was waived from injured reserve on October 31, 2019.
On November 1, 2019, Gordon was claimed off waivers by the Seattle Seahawks. In Week 15 against the Carolina Panthers, Gordon caught one pass for 58 yards and threw a pass that was intercepted by safety Tre Boston during the 30–24 win. On December 16, 2019, Gordon was suspended indefinitely for violating the NFL's policy on performance-enhancing drugs and substance abuse, his fifth suspension for violating the policy.