It has been nothing short than a difficult last couple of seasons for former All-Pro running back Adrian Peterson that has made his NFL future quite murky.

Things appear to be taking another step into uncertainty as Vinnie Iyer of Sporting News speculates that Peterson likely will not be brought back by the Arizona Cardinals next season due to the pending return of Pro Bowl running back David Johnson.

With David Johnson ready to take over feature duties again, Peterson won't be retained coming off a season-ending neck injury. He'll be looking to stick with another team as he turns 33 in March.

The 32-year-old still has one more year on his two-year, $7 million deal that he had originally signed with the New Orleans Saints last offseason before being moved to the Cardinals. In six games with Arizona, he notched 448 rushing yards on 129 carries with a pair of touchdowns. Peterson started off strong with two performances with at least 130 yards in his first three games. However, his play declined over the next three games failing to break 30 rushing yards twice over that span.

On top of that, his season came to an abrupt end as he missed the final five games due to a nagging neck injury. The progressive decline in production along with his continued health problems and the eventual return of Johnson has pushed the team to consider moving on from Peterson.

Since he was acquired by Arizona, there has been the notion in place that this is a temporary stay as Johnson has established a firm grip hold on the starting job. In fact, the reason for the trade for Peterson was to provide some stability at the position while the 26-year-old was on the mend from a wrist injury.

Regardless of what transpires over the next few weeks, Peterson has already made it clear that he plans to play four to five more seasons. There should be several teams interested in his services as a proven running back that has shown that he has plenty left in the tank.