MINNEAPOLIS — Adrian Peterson’s suspension from the National Football League triggered a courtroom clash Friday over the extent of the NFL’s power and authority.

With Peterson watching silently, the hourlong hearing — the first in a lawsuit filed against the NFL in U.S. District Court in Minneapolis — gave attorneys for the league and the NFL Players Association (NFLPA) their first opportunity to make their case in person to Judge David Doty.

The players’ union wants Doty to send the case back to an arbitrator to overturn the suspension the NFL handed down to the Vikings star running back nearly three months ago.

“They can’t have a lawless system . where they just make it up on their own,” said NFLPA attorney Jeffrey Kessler about the NFL not abiding by the league’s collective bargaining agreement.

In response, the NFL argued that the case doesn’t belong in court, but rather in arbitration, which Peterson already got.

Which side Doty agrees with is likely to have major ramifications not just for Peterson, but for other NFL players’ disciplinary cases.

Outside the downtown courtroom, a less serious scene faced him as he and his wife, Ashley, greeted fans sporting purple jerseys or signs in support, shouting “MVP! MVP!”

“We love you, AP! You can always call Minnesota home!” another shouted.

Justin Pruden of St. Paul, Minn. stopped by to show his support and to get a football signed by the star. “I don’t support what he did,” Pruden said of Peterson’s whipping of his son, the root of the case.