The suspension comes after the 23-year-old Gordon, who led the NFL with 1,646 receiving yards last season, argued he failed a drugs test because of second-hand marijuana smoke.
The league said in a statement that Gordon's "eligibility for reinstatement will be determined following the 2014 season."
Gordon, who has a history of suspensions and misdemeanors, said in a statement: "I would like to apologize to my teammates, coaches, the Cleveland Browns organization and our fans.
"I am very disappointed that the NFL and its hearing officer didn't exercise better discretion and judgment in my case.
"I would like to sincerely thank the people who have been incredibly supportive of me during this challenging time, including my family, my agent, my union, my legal team, and the Cleveland Browns staff."
Gordon was selected by Cleveland in the second round of the 2012 supplemental draft following a number of positive drug tests while playing US college football at Baylor and Utah.
He was suspended for the first two games last year for failing another drugs test. He claimed to have inadvertently ingested codeine contained in cough syrup.
He was also charged with drink driving last month in North Carolina.