A court hearing Friday could finally bring a definitive ruling in the NFL lockout and create the kind of leverage that could force a compromise after months of preliminary jousting.

The hearing in St. Louis will not produce an immediate ruling - that will likely take several weeks - but once a decision is in, it will more firmly establish who has the legal upper hand in the dispute between NFL owners and players. That could compel the losing side to give ground and set the stage for a compromise to end the owners' nearly three-month-old lockout.

"This is probably the most crucial round to date," said Robert Boland, who teaches classes on collective bargaining, antitrust cases, and the business of football at NYU's Tisch Center.

"I would hope that once this decision comes down, probably in late June, it spurs meaningful negotiations on both sides," said Andrew Brandt, a sports business analyst for ESPN and a founder of the National Football Post.

The hearing centers on the April injunction issued by U.S. District Judge Susan Richard Nelson. Owners have successfully put that decision on hold - leaving the lockout in place - and now hope to have it thrown out by a three-judge panel from the U.S. Court of Appeals for the Eighth Circuit. Two of the three judges strongly indicated in a previous decision that they favor the owners.

If the players somehow prevail, though, the injunction takes effect, lifting the lockout and forcing owners to resume league business such as trades, free agency, and supervised offseason training. Owners would lose their biggest source of leverage.

"If the players win this, I see a settlement fairly quickly," Boland said.

If the owners win, however, the lockout could be in place indefinitely. That means players will have to consider a September without pay, creating pressure to compromise before the season.

"If the NFL wins, the pressure of the lockout remains on the players," Boland said.

On the other hand, with their legal options limited after this hearing, Boland said, the players' only leverage might be to fight into the season and hope financial losses force the owners to give some ground. In past disputes, NFL players have caved under financial pressure.

Free-agent safety Quintin Mikell said players were prepared for a long fight this time, if necessary.

"You're going to have to have a little bit of struggle to get progress, so I know guys that are prepared to do whatever needs to be done to get the situation handled the best way possible, and that's for both parties," said Mikell, a former Eagles union representative.

After Friday's hearing, the losing side could appeal to the full Eighth Circuit or the U.S. Supreme Court, but both would be long shots, according to legal experts. A ruling on damages in a suit over television contracts is pending, but that decision also could be appealed, leaving Friday's hearing and eventual decision as the focal point.

"There don't seem to be any other key calendar dates ahead," Brandt said.

Contact staff writer Jonathan Tamari at 215-854-5214, jtamari@phillynews.com or @JonathanTamari on Twitter.