Per ESPN's Courtney Cronin, by recording eight sacks and playing more than 57 percent of the team's defensive snaps, Griffen hit two benchmarks in his contract that allowed him to void the final three years of his deal and become a free agent.
Cronin did note there's a "belief" the Vikings will be able to work out a new deal at a reduced price to keep Griffen.
Per Michael Ginnitti of Spotrac, with Griffen opting out of his deal, the Vikings were able to create $13 million in cap space this offseason.
Having that money available is huge for Minnesota's front office, which is still facing a difficult salary cap situation if it attempts to add players in free agency.
Even without Griffen's salary on the books, Spotrac ranks the Vikings 30th in the NFL with just $736,556 in available cap space.
Pro Football Talk's Mike Florio speculated last June the Vikings could attempt to release or renegotiate deals with Riley Reiff, Linval Joseph and Xavier Rhodes to free up salary.
Those three players account for nearly $39 million in 2020 cap space, but their combined dead cap total is only $11.6 million, per Spotrac.
Griffen, 32, has spent his entire 10-year career with the Vikings. The four-time Pro Bowler has recorded at least eight sacks in six of the past eight seasons.