The terms of Griffen's contract were not disclosed.
Griffen, 33, was selected by Minnesota in the fourth round of the 2010 NFL draft and spent a decade with the Vikings. From 2010 to '19, Griffen totaled 74.5 sacks, which ranks seventh in franchise history. He was named a Pro Bowler four times in Minnesota, including three straight seasons from 2015 to '17.
In February 2020, Griffen opted out of his contract and became a free agent. He signed a one-year deal with the Dallas Cowboys in August 2020 and was traded to the Detroit Lions two months later. In 14 games last season, Griffen registered six sacks, 33 tackles (seven for loss) and 14 quarterback hits.
Griffen said he was waiting for the "right fit" as a free agent and noted how difficult last year was having to move his family from Minnesota to Dallas to Detroit in the middle of a pandemic. His familiarity with the Vikings' scheme and close relationship with players like Danielle Hunter and defensive line coach Andre Patterson drew him back to Minnesota.
"Honestly, I wanted to be here," Griffen said. "I really wanted to be here. I felt like this was the best fit for me throughout the whole league. I really wanted to be here and I'm excited to be back. I'm just happy that things worked out the way they did and they welcomed me back with open arms."
As Griffen reflected on why he left Minnesota instead of taking a pay cut after opting out of his previous deal, the defensive end expressed regret with his decision.
"I left because I thought the grass was greener on the other side, to be honest, and it wasn't," Griffen said. "Going to Dallas, going to Detroit, the grass wasn't greener. I didn't get the love that I got here with the fans, with the coaches, with the players and the grass wasn't greener. I learned I'm back home and I'm happy to be home. I should have stayed last year, to be honest. Where people love me, where the fans love me, where you guys love me. I should have stayed but I worked hard. I made sure that I was productive enough. I should have stayed but I'm happy to be back."
One of Minnesota's top position questions in training camp is determining who will start opposite Hunter at defensive end. Stephen Weatherly and D.J. Wonnum have been the front-runners throughout the preseason, but the team left the door open for more competition at that spot when it brought in Griffen for a workout last week.
Wearing an unfamiliar No. 58, which he noted was a "little bit" weird, Griffen was at practice Monday and participated in light individual work. Coach Mike Zimmer said Monday that the Vikings plan to use Griffen as a "situational" pass-rusher. Griffen said he'll play "wherever they want me."
"If I didn't think he could help us, we wouldn't sign him," Zimmer said.
Griffen met with Vikings brass last week following his workout to confirm, "that my head was in it. That I'm in a good place." The defensive end took a month-long hiatus during the 2018 season to focus on his health and wellbeing after the Vikings ordered him to undergo a mental health evaluation and two separate incidents involving police authorities led to him being hospitalized.
Griffen opened up about his struggles last year and told NFL Network that he lived in a sober house for three months beginning in Oct. 2018.
Earlier this offseason, Griffen composed a handful of insulting tweets where he called Vikings quarterback Kirk Cousins "ass" and claimed that Zimmer never wanted to sign the QB. The defensive end said he planned to speak to Cousins and apologize.
"I haven't really talked to him yet but I'm going to get around to doing that," Griffen said. "Apologize to him, apologize to Coach Zimmer, [general manager] Rick [Spielman] about what I said. I take full ownership in that. I've still got to talk to Kirk and apologize to him about that."