The Cardinals will save $2.9 million in cap space by cutting him, per Spotrac.com.
Peterson's future in Arizona was always murky. For one, he's a 32-year-old running back who was placed on injured reserve in December with a neck injury after just six games with the Cardinals. He rushed for 448 yards and two touchdowns after being acquired in a trade with the New Orleans Saints.
But superstar David Johnson will also return from injury in 2018, reclaiming his place as the team's feature back and focal point on offense. Johnson, 26, was one of the best offensive playmakers in the NFL in 2016, rushing for 1,239 yards and 16 touchdowns while adding 80 receptions for another 879 yards and four scores.
With Johnson returning, keeping Peterson in a backup role as the team's most expensive running back makes less sense for a Cardinals team that could also add depth in the draft or add cheaper players in free agency.
As for Peterson, it's fair to question how much he has left in the tank. He was barely utilized by the Saints in his brief tenure with the team, relegated to the bench behind Mark Ingram and Alvin Kamara. Peterson averaged just 3.4 yards per carry in 2017 and has appeared in just 13 games over the past two seasons, with a meniscus injury costing him much of the 2016 campaign.
His days as a headliner in the backfield are over. For teams seeking a veteran backup this offseason, however, Peterson could be an intriguing option.