The future of Adrian Peterson with the Minnesota Vikings is up in the air as he's scheduled to earn a non-guaranteed salary in 2015 worth $15.4 million against the cap.

Peterson will be welcomed back by Mike Zimmer.

"Adrian was always great with me. I think he's a good person," Zimmer said, via ESPN.com. "I think obviously he's a great running back, and if it works out that way and things work out and he gets his life in order -- that's the most important thing, he gets his life in order, he gets the opportunity to come back -- then I will be in his corner whatever the decision is made.

"I think he would add value to any team, to be honest with you. I think the kid's a heck of a football player."

The NFL Players Association has filed a lawsuit against the NFL in U.S. District Court in Minneapolis, challenging an arbitrator's decision made Friday to uphold Adrian Peterson's suspension by the league.

The lawsuit comes as ABC News has obtained a recording of the Nov. 12 phone call between Troy Vincent and Peterson in which the NFL executive tells him that he would be reinstated after a two-game suspension and get credit for his time on the commissioner's exempt list.

Vincent made the promise with the additional request that Peterson attend a Nov. 14 meeting with commissioner Roger Goodell to discuss the child abuse case in which he pleaded no contest in Texas to misdemeanor reckless assault for physically disciplining his 4-year-old son with a wooden switch. Peterson declined to attend the meeting, however, citing uncertainty about the NFL's intent to question him, and the league issued a six-game suspension to the running back on Nov. 18.

Adrian Peterson has been so disappointed by the NFL's disciplinary process that he's considering retirement.

In a 60-minute phone interview with ESPN, Peterson said he plans to file a lawsuit against the league, adding he wasn't sure if he could trust the NFL's process for reinstatement. If a lawsuit would eventually put the 2012 NFL MVP's chance for reinstatement at risk, Peterson said he would consider walking away from the game altogether.

"I've considered retiring from the NFL," Peterson said. "I still made $8 million dollars this year. I've thought about getting back into the real estate (business in Texas) I'm already in. That's something I've been interested in, something I'm involved in. I've thought about getting back into that. I've thought about going after the Olympics -- you only live once. It might be time for me to pursue that, as well. I love playing football, don't get me wrong, but this situation is deeper than that. For me, it's like, 'Why should I continue to be a part of an organization or a business that handles players the way they do? Making money off the field anyway, why not continue to pursue that (Olympic) dream and pursue other dreams and hang up the cleats?'"

Adrian Peterson's appeal of his suspension has been denied.

NFL spokesman Greg Aiello announced on Friday afternoon that Harold Henderson has denied Peterson’s appeal of the suspension without pay through at least the end of the 2014 season that was handed down by the league in November. Henderson, a former league official, was appointed to hear the appeal by Commissioner Roger Goodell.

“I conclude that the player has not demonstrated that the process and procedures surrounding his discipline were not fair and consistent,” Henderson said in a statement released by Aiello. “He was afforded all the protections and rights to which he is entitled, and I find no basis to vacate or reduce the discipline.”

Peterson will be eligible for reinstatement on April 15.

As Adrian Peterson awaits a ruling from arbitrator Harold Henderson on his appeal, he has made it clear he wants to get back on the field.

"He's told us he wants to play this season," union executive George Atallah said Tuesday, via the St. Paul Pioneer Press.

The Minnesota Vikings have just three games remaining this season.

Ian Rapoport reports that the Vikings' football people would like to see Peterson remain with the franchise.

The Minnesota Vikings have placed Jerick McKinnon on season-ending injured reserve with a lower back injury.

McKinnon, a third-round draft pick out of Georgia Southern, was leading the Vikings in carries (113), rushing yards (538) and yards per carry (4.8). Among rookie backs, he ranks third in rushing yards, behind Jeremy Hill and Tre Mason.

Adrian Peterson's future with the Minnesota Vikings is in doubt, but he wants to play for at least another half-decade.

"People say, 'Oh, running back hits 34, 35 (and he's done). When you get to 30, you go down.' I don't believe that," Peterson recently told USA TODAY Sports' Tom Pelissero. "I believe I'm just now here in my prime. I believe these next five or six years -- or however long I decide to play -- it's going to be the same production and I'm going to do even better than I did before in my 20s."

Peterson turns 30 in March. Studies have shown that running-back production decreases by 15 percent at age 28, 25 percent at age 29 and 40 percent by the age-30 wall.