The Orioles and MASN filed their appellate brief arguing that the case should be heard in an independent forum.
MLB took the forceful step of informing all parties that it will proceed with a new panel hearing unless the court bars it.
Since the MASN dispute began, the Nationals payroll has jumped from 20th to fifth in baseball.
This step will only drag out the dispute longer.
"We are intent on making sure that the agreement that gets the Nationals a fair market value for their TV rights is enforced."
The judge tossed out the June 2014 MLB panel ruling that gave the Nationals higher TV rights fees.
All three on-air broadcasters are returning next season, their third season together.
The back-and-forth continues while a New York Supreme Court judge's decision is awaited.
Manfred told reporters Thursday "sooner or later MASN is going to be required to pay those rights fees" to the Nationals.