In a setback for Sonics owners' attempts to make a fast break from KeyArena, U.S. District Judge Ricardo Martinez ruled Monday the team's lease fight with Seattle must remain in federal court instead of going to binding arbitration.

Team owner Clay Bennett sought arbitration last month, hoping to win a ruling that would allow his ownership group to buy its way out of the KeyArena lease after the 2007-08 season, which begins Wednesday. City officials filed a lawsuit to block the arbitration.

In his written ruling, Martinez agreed with the city that the dispute was not subject to arbitration because it centers on Article II of the lease, which says the team must play all home games at KeyArena through September 2010.

Martinez called the Sonics' arguments to the contrary "as errant as a typical Shaquille O'Neal free throw."

The ruling does not settle the underlying dispute in the lawsuit — whether the city can use the lease's "specific performance" clause to reject a buyout and force the Sonics to play out the remainder of the 15-year lease.

"It's important to note that the decision addresses the forum in which the dispute will be decided, not the merits of the case," said Sonics attorney Brad Keller, in a written statement.

Keller said team owners are "confident that they can perform their financial obligations under the lease" but that the city could not force the team to play its final two seasons at KeyArena.

But keeping the case in federal court could delay efforts by Bennett to relocate the Sonics to Oklahoma City. Arbitration could have been wrapped up by late March. Federal lawsuits frequently drag out for years.

Seattle City Attorney Tom Carr said that Martinez's ruling, while welcome for the city, will not necessarily determine the outcome of the larger case, which now will turn to arguments about whether the value of retaining the Sonics at KeyArena can be measured in cash.

Carr said the city likely will seek depositions and other evidence as part of the discovery process. That could take a while.

"We'll want some time. I assume the Sonics will want this decided tomorrow," Carr said. "I don't think that's going to happen."

Bennett has said he'll file with the NBA for permission to move the Sonics after this season unless he gets an arena deal by a Wednesday deadline. Bennett set the Oct. 31 deadline last year after leading a group of Oklahoma City businessmen in buying the Sonics and Storm.

The Storm's KeyArena lease also runs through 2010, but is not an obstacle because it allows the team to opt out after any season.

Monday's ruling was greeted enthusiastically by the fan group Save our Sonics and Storm, which had pushed city officials to strictly enforce the KeyArena lease.

"As fans we're looking for some wins in this situation, some inspiration. This is a big one," said Brian Robinson, co-founder of the group.

Robinson said he hopes "holding the line" on the lease will force Bennett and politicians to start talking about a long-term solution.

"That means a new arena and we're hoping our political leaders will take care of that," he said.

Jim Brunner: 206-515-5628 or jbrunner@seattletimes.com