(Update: The Packers released Franklin on Friday.)
Coach Mike McCarthy made the announcement after Thursday's final minicamp practice, saying he had "unfortunate news" about Franklin, who joined the team as a fourth-round pick out of UCLA last year and was injured on a kickoff return against Minnesota on Nov. 24.
"All the information has come in, we've had a chance to sit down and talk to Johnathan the last couple days. He will not be back with us," McCarthy said. "I can't say enough about him as a person. He's as classy of a young man that's walked through these doors."
Franklin carried 19 times for 107 yards and a touchdown as a rookie last season. His biggest game came at Cincinnati on Sept. 22, when pressed into action because of injuries to Eddie Lacy and James Starks. Franklin carried 13 times for 103 yards but lost a fourth-quarter fumble that was returned by the Bengals for what turned out to be the game-winning touchdown.
Franklin's agent, Kenny Zuckerman, told ESPN.com that his client would be waived by the team and that Franklin would visit other doctors "just to get peace of mind."
Franklin posted a message to his Twitter account Thursday confirming the career-ending nature of the injury.
"I have been ruled out of returning for the 2014/15 season and returning to play in the NFL," Franklin wrote. "But I understand God knows what he is doing and for now he has another platform for me to step upon. I ask that you all pray for me during this transition."
The news hit Franklin's teammates hard, including defensive end Datone Jones, who played with Franklin at UCLA and has known him since the two were high-schoolers in the Los Angeles area.
"He's not just a football player to me, man. He's a brother," Jones said. "We shared a special bond at UCLA. It was a special brotherhood. When I found out the news, for me, I didn't really care about the injury anymore because I knew he was OK in that area. But I wanted to see where his mind was at. His spirits were up, he felt like God had opportunity for him."
Franklin, who was UCLA's all-time leader in both career rushing and all-purpose yards, talked openly in the past about wanting to someday be the mayor of Los Angeles. On the day he was drafted, he spoke about his passion for his hometown and the opportunity to someday make a difference there.
"I grew up in a rough neighborhood. I saw so many kids from the inner city fall in to trouble. You see a lot of negative things happening," Franklin said at the time. "And I said, 'You know what? I think I want to have an impact on the community and the city.'