The suspension, which leaked last week to the media, is effective immediately. Kerley will be eligible to return to the active roster on Dec. 11, the day after the Jets face the Denver Broncos.
Kerley, in a statement, said he tested positive for Turinabol, but he took issue with the suspension, saying he was "shocked" because he's "never knowingly taken any banned substances."
"I am 5-foot-9 tall and 180 pounds, and I have never used steroids in my life," he said. "I'm a good athlete, but anyone can look at my body composition and tell that I'm not a steroid user. While I did not have enough time prior to the deadline to resolve this case, I fully intend to investigate this matter until I am able to figure out what caused the positive test, because I know that I have done nothing wrong.
"When I find out what substance was tainted, I will pursue all remedies at that time because this is not right. I have and will always be a clean player, and I look forward to returning to the Jets to play against the Saints next month."
Coach Todd Bowles said the organization was aware of the pending suspension for "quite some time."
Kerley is a valuable part of the offense because he's the No. 3 receiver. He's fifth on the team with 22 receptions for 217 yards and one touchdown. He's also the primary punt returner.
The top two receivers are Jermaine Kearse and Robby Anderson. Rookies Chad Hansen and ArDarius Stewart will see more time on offense, according to Bowles, who said the Jets could sign a receiver or promote one from the practice squad.
They have three on the practice squad: Jalin Marshall, Damore'ea Stringfellow and JoJo Natson.
Kerley, who will turn 29 on Wednesday, played with the Jets from 2011 to 2015 and returned at the start of the season after spending a year with the San Francisco 49ers.