Josh Gordon will miss the start of Cleveland Browns training camp to focus on his "overall health and treatment," the wide receiver said in a statement released on Monday.
Gordon was reinstated to the NFL last season having seen his career heavily affected by substance abuse issues.
But, with the Browns set to open camp on Thursday, Gordon posted on Twitter: "I will not be in Cleveland for the start of training camp. Rest assured this too is a part of my overall health and treatment plan.
"I appreciate the awesome support I have received from team-mates, friends, fans, and the Browns organisation. Just like you, I am excited to start the season and I have every intention of being ready and available to join my team-mates soon to help bring winning football to our fans.
Thanks again.. See ya soon..— Flash Gordon (@JOSH_GORDONXII) July 23, 2018
"With the help of the NFL, NFLPA, and the Browns organisation, I have been able to utilise the resources available to me that will ensure my well-being on and off the field.
"By continuing to follow the plan set up by our medical director and his team and taking this time before this season starts, we believe it will help me maintain the progress I've made for not only today but for many years to come. Thank you all for your patience, love, and support! Go Browns!"
Browns general manager John Dorsey added in a statement: "We will continue to support Josh as he receives the care needed to maintain his progress. We are going to respect his privacy while he is away from the team. Josh will be placed on the non-football illness reserve list until he is ready to return."
NFL spokesman Brian McCarthy told Cleveland.com there is "no timetable" for Gordon's return but the team will "address the matter at the appropriate time."
Gordon had served an an indefinite suspension since 2014 for repeated violations of the NFL's substance abuse policy but was activated for the final five games of last season, catching 18 passes for 335 yards and a touchdown in that time.
The 27-year-old, a first-team All-Pro selection in 2013, signed an exclusive rights tender with the Browns in April.
|Browns trade running back Hyde to Jaguars|
|Mourinho: I´d love to have Hazard at Manchester United|
|Hamilton´s title chances enhanced by Vettel´s grid penalty|
|Deja vu for Enisei as La Rochelle inflict another thrashing|
|Five-star Jovic makes Bundesliga history|
|Liverpool´s scoring slump no concern for cautious Klopp|
|He´s the Special One - Sarri insists he is not on Mourinho´s level yet|
|Second-half blitz guides Leicester to European success|
|Sheffield Wednesday 1 Middlesbrough 2: Besic, Assombalonga see off Owls|
|Goerges rallies to reach Luxembourg Open final, Jabeur makes history|
|Howe: Transfer speculation will not disrupt Ake|
|´Do we really want opera every night?´ - Klopp not changing Nations League view|
|Vile and abhorrent – Chelsea´s Carney responds to online abuse|
|Giants WR Beckham Jr. explains why he might cramp up: ´I really don´t like water´|
|Man City pay training-pitch tribute to Joe Hart|
|Neymar to be rested as Tuchel rubbishes Ballon d´Or concerns|
|Sarri ´not interested´ in Christensen father´s quit threat|
|Cardinals fire offensive coordinator McCoy after 1-6 start|
|Neymar return unlikely, but anything can happen – Valverde|
|Bairstow a doubt for fourth ODI|
|Manchester United fined for late arrival and delayed kick-off against Valencia|
|Australia-Pakistan chat not ´especially polite´ - Sarfraz|
|Pogba relishing ´pressure game´ against in-form Hazard|
|Don´t bet on Cardiff survival, warns Warnock|
|Buffon enjoying Tuchel´s methods at PSG|
|RIP to Wimbledon epics! Isner feels like The Undertaker following final-set tie-break rule|
|Sevilla performance sealed Bernat´s Bayern exit - Hoeness|
|Keita set to miss out as Liverpool monitor injured stars|
|He didn´t want to be here – Guardiola doubts Sancho will return to Manchester City|
|Sarri: Manchester United are the best in the Premier League|
|Mourinho salutes ´brave´ Shaw for ´best possible´ response to criticism|
|No Ballon d´Or distractions for Griezmann, insists Simeone|
|Wigan stand by Hardaker as full-back prepares to undergo rehabilitation|
|Barcelona deny Neymar talk|
|Hazard can win the Ballon d´Or as a Chelsea player, insists Sarri|
|De Bruyne in contention to start in Manchester City´s clash with Burnley|
|Neymar needs to mature to reach Messi levels - Xavi|
|We have a hell of a lot to do - Paine slams Australia batting|
|Kerber and Osaka to meet at WTA Finals|
|Lorenzo out of Japanese MotoGP|
|Real Madrid handed Africa trip in Copa del Rey|
|Allegri: Ronaldo has sharpened Juventus focus|
|No Wade in Wasps squad amid NFL reports|
|Rooney: Five of us controlled Man United dressing room|
|Bayern bosses launch scathing attack on ´disrespectful´ media|
|Saints lock in Lawes to new deal|
|Adelaide United 1 Sydney 1: Debutant Le Fondre rescues a point|
|Madrid can´t look back, only forward - Lopetegui confident of revival|
|Wimbledon to introduce final-set tie-breaks|
|Abbas inspires Pakistan to series victory|
|Madrid boss Lopetegui hopeful on Bale availability|
|Mood is positive at Bayern, insists under-pressure Kovac|
|LeBron offers food for thought after losing Lakers debut|
|Bolt future not an immediate concern for Mariners|
|Hazard: I could finish my career at Chelsea|
|Buffon hoping to avoid Champions League final against Juventus|
|Wilshere not ready for West Ham return|
|Chelsea v Manchester United: Hazard better under Sarri than he ever was with Mourinho|
|The big Friday Premier League quiz|
|Khawaja suffers meniscal tear, doubt for India series|
|Babbel: Klopp must win trophies now at Liverpool|
|LeBron makes spectacular start on Lakers debut, but LA fall to Trail Blazers|
|Broncos thrash Cardinals to end losing streak|
|Price leads Red Sox past Astros and into World Series|
|LeBron makes fast start on Lakers debut with two massive dunks|
|Real Salt Lake 4 New England Revolution 1: Hosts boost play-off chances|
|Simmons gets triple-double in win over Bulls|
|´Ambitious´ Maguire wants Champions League football|
|Henry praises ´charismatic leader´ Falcao|
|WATCH: Cardinals WR Fitzgerald tackles former QB Warner on sidelines|