He will be eligible to apply for reinstatement prior to the start of the 2014 season.
Blackmon, 23, was suspended four games at the beginning of this season for a substance abuse violation, which was his second violation in less than a year.
He said then that getting in trouble is "not who I'm going to be."
Blackmon has about $10 million left to be paid on a four-year, $18.5 million contract.
“All of us who are a part of the Jaguars family care very deeply about Justin and his well-being," Jaguars general manager David Caldwell said in a statement. "That said, he must be held accountable and accept the consequences announced today by the NFL. His suspension will provide him the opportunity to receive the attention and professional treatment necessary to overcome his challenges, and we will support him during this time. The Jacksonville Jaguars will evaluate Justin's status once he has successfully met the criteria to be considered for reinstatement to the league.”
Blackmon issued a statement apologizing for the latest suspension:
“I want to sincerely apologize to Mr. Khan, my teammates, my coaches and to the Jaguars fans for not utilizing the resources that I was provided to overcome my challenges,” Blackmon said in a statement released to Pro Football Talk. “I am determined to overcome the issues that have resulted in this situation, and I truly appreciate the support that the Jaguars and my agent have shown me. “I will address these matters with the type of intensity I usually direct toward my on-field play so that I can be ready to be a productive member of the team and community next season. Again, I am truly sorry to Mr. Khan, my teammates and coaches and to the Jaguars fans for the impact of my situation on the team as well as to my family and friends and those that have been there for me during these challenging times. Nobody is more disappointed with all of this than me.”