Gordon, who was reinstated from an indefinite suspension by NFL commissioner Roger Goodell on Aug. 16, released the statement on social media two days before the Patriots host the Pittsburgh Steelers in the season opener.
"Before the 2019 season starts, I would like to address an issue that arose toward the end of last season," Gordon wrote. "It's been well documented that I have battled substance abuse for quite some time. Unfortunately, I did not take the time to focus on a solution to my problem until this past year.
"I am eternally grateful for the constant support from the NFL, NFLPA and the Patriots organization. I also want to thank my family, friends and all the fans who supported me while I addressed this issue. Going forward, I will not be discussing the details of my past. I plan to focus on the present and getting better every day."
Gordon ended the statement by saying, "I hope people will judge me on what I do now and in the future."
The league has suspended Gordon multiple times for violations of its drug policies since entering the NFL with the Cleveland Browns in 2012. He sat out the entire 2015 and 2016 seasons due to suspensions.
The Browns traded Gordon to the Patriots in September 2018. He started 11 games and recorded 40 receptions for 720 receiving yards and three touchdowns before the NFL suspended him again in December for violating the league's substance abuse policy.