The tussle over Adrian Peterson’s suspension from the National Football League will play out Friday for the first time in a Minneapolis courtroom.

The NFL Players Association (NFLPA) is suing the league in federal court on behalf of the Minnesota Vikings star running back, asking a judge to overturn the suspension handed down nearly three months ago.

The decision could affect not only Peterson, the league’s 2012 Most Valuable Player, but also set a precedent for future NFL disciplinary cases.

“This case is viewed by many as a stalking horse for other legal battles between the players union and the league,” said Marshall Tanick, a Minneapolis employment lawyer who has represented athletes. “The stakes are big for both sides.”

A Texas grand jury indicted Peterson, 29, last September on a felony charge after he whipped his 4-year-old son. He was placed on the Commissioner’s Exempt List while his court case played out. After pleading no contest in court on Nov. 4, he was suspended by the NFL until at least April 15.

Peterson and the NFLPA have twice tried unsuccessfully to fight the NFL’s actions — first in a union grievance over keeping Peterson on the exempt list, and secondly in an appeal of the suspension.

Now Peterson is taking his case to federal court, hoping U.S. District Judge David Doty, who has handled several NFL cases, will side with the union and order Peterson’s immediate reinstatement. The NFL is asking the judge to reject the case, arguing that it doesn’t belong in court.

While Doty isn’t expected to make a decision at Friday’s first hearing on the lawsuit, the NFLPA is pushing for a quick resolution. The league’s new year, and free agency, starts March 10.

The case has set off a dispute over whether Peterson’s disciplinary process was fair and has called into question the extent of NFL Commissioner Roger Goodell’s authority. The union accuses him of yielding to public criticism of the NFL with Peterson’s suspension, an “inconsistent” and “unlawful” disciplinary action.

If the judge sides with the NFL, “it solidifies Roger Goodell’s authoritative power over the NFL,” said Minneapolis attorney Lee Hutton III, who has represented professional athletes including former Vikings players Hank Baskett and E.J. Henderson. “It shows the NFL will take certain player discipline very seriously, especially in this time frame when we have had such public off-field problems. It’s a case that’s going to have implications for any NFL athlete and the team. … Everyone is going to watch this.”

Peterson was fined $4.1 million, or six weeks’ pay, from his $11.75 million salary last year. His contract runs through the 2017 season, but there’s no guaranteed money remaining. His salary for the 2015 season is $12.75 million and the Vikings would take a staggering $15.4 million salary cap hit. They could reduce the salary cap hit by reworking his contract, if he and his agent, Ben Dogra, are agreeable. Or the Vikings could cut him, making him a free agent.

Suspended until April

Peterson only played one game last season. In September, news surfaced that he whipped his 4-year-old son with a switch, leaving the boy, who lives with his mother in Minnesota but was on a visit to Texas, with bruises and scars for days.

A Twin Cities doctor who later saw the injuries contacted authorities. A Texas grand jury indicted him in early September on a felony charge of injury to a child.

After a brief reinstatement was protested publicly, he was placed on the exempt list Sept. 16. The union filed a grievance to have Peterson taken off the exempt list, but lost.

Then, on Nov. 18, the NFL suspended Peterson after his no contest plea to a misdemeanor charge of reckless assault.

His suspension lasts until at least April 15, if he fulfills requirements such as counseling and therapy.

In a second effort to fight the NFL, Peterson appealed. But in December, an arbitrator upheld the suspension, saying Peterson’s conduct toward his son was “brutal” and “arguably one of the most egregious cases of domestic violence in this Commissioner’s tenure.”

Challenging the NFL

The NFLPA fired back, suing the NFL. In the 75-page lawsuit, the union argues that the court must reinstate Peterson because the arbitration decision wasn’t fair, violated the collective bargaining agreement and the biased arbitrator exceeded his authority. It also states that Peterson had no idea when he disciplined his son in May that, in August, Goodell would release a new policy on players facing increased discipline for domestic violence. The suit argues that, before this new policy, Peterson would have been suspended for no more than two games.

The union added Jan. 26 that the arbitration was “designed to quell public criticism aimed at the League and the Commissioner, [and] was rubber-stamped by an NFL insider,” referring to arbitrator Harold Henderson, a former league official.

The NFL responded in court documents, asking the judge to dismiss the union’s request, citing federal labor law.

It dismissed the union’s objection over fairness and also dismissed its claim that the arbitrator was biased as based on “supposed appearance of bias, as opposed to actual bias.” The NFL said that the commissioner has the authority to discipline players for “conduct detrimental to the integrity of, or public confidence in, the game of professional football.”

“I think it’s going to be very difficult for the federal court to overturn the arbitrator,” Hutton said, adding that Doty could uphold the process, or send it back to arbitration.

The Vikings have said they’d like Peterson to return to the team in 2015, but have stopped short of saying that will happen once he’s eligible to be reinstated.

“I know that Adrian is a good person, just being around him,” Vikings General Manager Rick Spielman told reporters in January. “I know he’s done a lot of good in this community. What he did — he just came out and said he made a mistake. As [coach Mike Zimmer] had stated earlier, he has to get all that in order and then we’ll proceed from there.”