The Vikings made the announcement of Griffen's return on Tuesday after he missed five games.
"We have been in communication with Everson's medical professionals throughout this process and have relied on his recommendations regarding the appropriate next steps for Everson," Vikings general manager Rick Spielman said in a statement. "We are excited to welcome Everson back to the Vikings and to see him around teammates, coaches, and staff -- people who care deeply about his well-being. Our focus will continue to be on providing an on-going support system for Everson and his family."
"Being around my teammates and coaches is something I have missed for several weeks," Griffen said in a statement. "While this is an exciting and positive move forward for me, it is only the next step in a longer process. I look forward to once again putting in the work with the guys and contributing to this team in any way I can.
"My larger focus remains on addressing my personal health, and I'm hopeful the time will come when I feel comfortable sharing my story and using my platform to bring awareness to these issues. I continue to be extremely grateful for the constant support from my family, my teammates, the Vikings organization and our tremendous fans."
The Vikings (4-2-1) face New Orleans on Sunday night.
Griffen was treated at a mental health facility after he exhibited erratic behavior in a series of incidents that caused his wife to call police.
In one incident, Griffen allegedly threatened to shoot hotel employees, although no gun was found. After that incident, Griffen allegedly tried to break into the home of Vikings teammate Trae Waynes.
Griffen has been named to the Pro Bowl in each of the past three seasons, and he had a career-high 13 sacks in 2017. In two games this season, both as a starter, Griffen had one sack and six total tackles.