Earlier this offseason the Vikings announced that they would not be picking up Peterson's option.
The move seemed inevitable when the Vikings signed running back Latavius Murray to a three-year, $15 million deal on Wednesday night.
More than a week later, Minnesota has signed a new running back in Latavius Murray and Peterson is still without an National Football League contract for the 2017 season.
Peterson, 31, is a seven-time Pro Bowl player and three-time league rushing champion.
One of Del Rio's criticisms of the Raiders offense last season was they didn't play enough "big boy" football at times with power running. Coming off a 1,000-yard season in 2015, Murray became part of a three-man backfield with De'Andre Washington and Jalen Richard.
"Adrian is probably going to go down as one of the greatest Vikings", Spielman said. The former sixth-round pick has signed on with the Minnesota Vikings following the end of his four-year rookie contract.
Murray's contract is friendly to Minnesota, but it also sets the bar low for other running backs in the free agent market.
"Just making sure we got the details right, " Murray said.
"When I saw that maybe this could be a team I would be playing for, obviously you think about those different scenarios", Murray said.
There wasn't a thought in my mind to try and wear or ask for the #28.
Peterson visited with the Seahawks earlier this week, but they signed Eddie Lacy. Obviously, I know it's a business - that I've learned these last few days.
Obviously, he would have to be released, or they would have to make a trade for him, but Skip, I like this.
Last season, Murray doubled his number of rushing touchdowns from six to 12.
He has failed to eclipse 40 carries in two of the past three seasons because of suspension and injuries.
Is it the fact that the soon-to-be 32-year-old running back struggles to run out of the shotgun? "I came into Dallas (in 2003) and (hall of famer) Emmitt Smith was cut the year before I got there".