The 2018 season featured many ups and downs for running back Adrian Peterson. These contrasting moments were so severe that his future in the NFL is now extremely uncertain.

That cloudy future just turned for the worse as the Arizona Cardinals are expected to waive Peterson at some point over the next couple of months, according to Mike Jurecki of Arizona Sports Station 98.7.

Peterson had been acquired by the Cardinals during the 2017 season from the New Orleans Saints in exchange for a sixth-round pick. He was needed as the replacement for Pro Bowl running back David Johnson who went down for the year via injury.

In six games with Arizona, he piled up 448 rushing yards on 129 carries with a pair of touchdowns. He started strong with two performances with at least 130 yards in his first three games. However, his play tittered off over the next three games failing to break 30 rushing yards twice over that span.

On top of that, Peterson's season came to an abrupt end as he missed the final five games due to a bothersome neck injury. The decline in production paired with his health issues along with the expected return of Johnson has likely led to the team leaning toward parting ways with the seven-time Pro Bowler.

Peterson still has one more year left on his two-year, $7 million deal, which should make it less of a financial burden to go in that direction. This will put him on the open market for the second time in as many offseasons. He may once again struggle to find a nice fit on an NFL depth chart.

There will likely be teams interested in acquiring his services, but it will upon him to be more willing to take a secondary role at this stage of his career. Peterson has shown flashes of his former MVP form, but until he can prove he can stay healthy there will be the hesitations toward making him the workhorse running back.