Gordon later took to social media to say he was "thankful":
Jay Glazer of Fox Sports first reported the news of the wideout's reinstatement.
This comes after Mike Florio of Pro Football Talk reported on May 21 that Gordon planned on applying for reinstatement and was ready to play. The goal at the time was to be cleared before training camp started.
Gordon appeared in 11 games during the 2019 campaign for the New England Patriots and Seahawks, and Florio noted he played enough contests to qualify for unrestricted free agency.
However, Seattle signed him to a one-year deal in September even with his status still in the air.
The Baylor University product was suspended indefinitely in December 2019 after he violated the league's substance abuse policy. Gordon's lawyer, Adam Kenner, said the wide receiver had a relapse in 2019 following the death of his brother.
It marked the fifth suspension in eight years for the pass-catcher, who missed the entirety of the 2015 and 2016 campaigns because of the punishments.
He also played in just five contests for the Cleveland Browns in 2014 and again in 2017.
The suspensions largely prevented Gordon from capitalizing on his ceiling and building on his breakout effort in 2013 when he made the Pro Bowl in just his second season behind an NFL-best 1,646 receiving yards and nine touchdown catches.
Gordon also impressed as a rookie in 2012 with 50 catches for 805 yards and five touchdowns.
He was nowhere near that productive during the 2019 campaign with the Patriots and Seahawks, tallying 27 catches for 426 yards and one touchdown while primarily playing as a secondary option in both offenses.
Still, he is just 29 years old and without many games under his belt of late, meaning he could be relatively fresh and durable as he enters the next stage of his career. Gordon also won't be asked to do too much in Seattle's offense that already features DK Metcalf and Tyler Lockett, but he could be another dangerous weapon for Russell Wilson down the stretch.