Head coach Bruce Arians said Wednesday he has "no idea" whether the 32-year-old will be able to recover in time to play again this season, per ESPN's Adam Schefter.
There are three games remaining in the 2017 season and the 6-7 Cardinals are a long shot to reach the playoffs.
Peterson finished his Week 12 game against the Jaguars, but he was held out of practice the next week with a neck injury and has been inactive since. Arians was unspecific about the issue last week, noting there was no timeline for a return.
"He's walking around fine," the coach said, per Darren Urban of the team's official site. "It's a matter of taking a hit, and getting all his strength back."
The running back came to the Cardinals in a midseason trade from the Saints, rushing for 448 yards in six games after tallying just 81 yards in four with New Orleans. While he is a long way from being the four-time All-Pro he was with Minnesota, he remained effective when given an opportunity.
Unfortunately, injuries have been an issue for Peterson throughout his career and especially lately. He has only completed a 16-game season twice in the last eight seasons and missed 31 games due to injury over the last four years.
Considering his age and injury history, another extended absence could create even more question marks about his future.
Kerwynn Williams will remain the Cardinals starting running back with Peterson unavailable, with D.J. Foster and Elijhaa Penny getting snaps in the backfield as well.