Updated

(SportsNetwork.com) - David Doty continued to be a thorn in the NFL's side Thursday, vacating an arbitration ruling that went against suspended Minnesota Vikings running back Adrian Peterson.

From a legal standpoint it was a devastating rebuke of the league's actions and hardly the first by Doty, a pesky federal judge who actually cares about silly little things like the rule of law.

Understand judges are loathe to overturn arbitration rulings in collectively- bargained disputes, mindful of the Pandora's Box it could open. And they are steered to never overturn or vacate a decision if "the arbitrator is even arguably construing or applying the CBA and acting within their authority."

In the Peterson case, however, Doty was predictably appalled by the NFL's now almost consistent strategy of moving the goal posts based on public perception, all the while leaning on commissioner Roger Goodell's collectively-bargained broad discretion in handing out punishments.

Peterson was originally charged with reckless or negligent injury to a child for striking his 4-year-old son with a switch in May and was placed on the commissioner's exempt list in September.

He was then suspended by Goodell in November for violating the new policy after reaching a plea agreement in Texas. The NFLPA then filed an appeal on behalf of Peterson that was upheld by league-appointed arbitrator Harold Henderson in December.

When filing the lawsuit, the NFLPA accused the league of "making it up as it goes along," maintaining that Peterson's harsh punishment came as a result of the reaction from other non-related issues involving Ray Rice and Greg Hardy.

Doty agreed with that logic noting that Peterson was disciplined under the league's so-called "new personal-conduct policy," which was fueled by the reaction to Rice's original punishment more than anything else, for actions that happened before it even existed.

"Despite broad deference, the arbitration award was fatally flawed because it allowed for retroactive application of new NFL Conduct Policy," Doty explained.

And Doty also accused Henderson, who has been called a rubber stamp for Goodell by the NFLPA, of straying "beyond the issues submitted by the NFLPA and in doing so exceeded his authority."

"This is a victory for the rule of law, due process and fairness," the NFLPA said Thursday in a statement. "Our collective bargaining agreement has rules for implementation of the personal conduct policy and when those rules are violated, our union always stands up to protect our players' rights. This is yet another example why neutral arbitration is good for our players, good for the owners and good for our game."

You should never underestimate the pettiness of Goodell, though. The NFL is expected to appeal the decision made by Judge Doty, according to NFL Media, despite the fact that the league lost an insignificant battle in a war that's already won.

After all, for Peterson and the NFPLA, this victory was as hollow as it gets.

Remember A.P. was forced to sit out the majority of the 2014 season, and docked six game checks after the suspension kicked in. Meanwhile, his relationship with the Vikings was irreparably damaged because he believes higher-ups in the organization abandoned him during his time of need.

The veteran running back was eligible to be reinstated in about six weeks anyway and by all accounts Goodell was not planning to try to keep him off the field in '15.

A black-eye at the hands of Doty is nothing when you factor in the league already got everything it wanted. Peterson, as well as Rice and Hardy, was kept off the field last season and a revamped, far harsher personal-conduct policy was unilaterally implemented without union involvement in a true collective-bargaining process.

Dieting is supposed to be one game you win when you lose. The NFL just found another one.