The owners of the Rosecroft harness track have scotched plans to sell to the family of Peter G. Angelos, a negotiation that briefly landed the Baltimore Orioles owner at the center of Maryland's fractious slot machine gambling debate.

The eight-member board that oversees the racetrack voted Thursday night to reject the offer Angelos's wife and two sons made in June to buy the track for $13 million. The track owners returned a $500,000 deposit the Angelos family put down when submitting its bid.

Representatives on both sides said last night that the decision does not preclude the family from returning to the negotiating table but that the vote was a major setback.

"The message was our current offer has been rejected," said Gerard E. Evans, an Annapolis lobbyist who is representing the Angelos family. "We would like to continue discussions, but I guess the ball is really in their court."

Members of the Cloverleaf Enterprises board, which runs the Standardbred track in Prince George's County, were reluctant yesterday to discuss their decision, saying it was a private business negotiation.

Gerald Brittingham, the retired Washington area real estate executive who led the group that purchased the track in 1995 for $13 million, said last night he was "disappointed" that the two sides could not reach an agreement.

"There's not anger. It's disappointment, obviously, that we couldn't resolve the differences," Brittingham said.

"I respect a businessman for making a decision," he said of Peter Angelos. "We just had a difference of opinion. Our goal is to maintain live racing in this industry as long as we can. There are an awful lot of people whose livelihoods are at stake."

The track has been struggling for several years as interest in racing has dwindled. Matters grew worse when the owners locked horns with the Maryland Jockey Club over how to parcel out profits from simulcasting, which accounts for a significant portion of their business.

Salvation, the track owners have said, rests almost entirely in the hands of the Maryland General Assembly, which has considered making the track one of a half-dozen sites for legalized slot machine gambling. Angelos would be a powerful ally in that fight.

Not long after his family made its offer on Rosecroft, Angelos emerged as a significant player in intensive, behind-the-scenes, summer negotiations over legislation to legalize slots that has been pending in Annapolis for two years.

Those talks broke off this month when Gov. Robert L. Ehrlich Jr. (R) and House Speaker Michael E. Busch (D-Anne Arundel) could not agree on an approach to legalizing the machines.

Senate President Thomas V. Mike Miller Jr. (D-Calvert) could not be reached yesterday, but he has said in earlier interviews that he welcomed Angelos's involvement in the slots debate, predicting his clout could prove persuasive with lawmakers.

But Angelos has said that if the Rosecroft deal falls through, it might end his family's flirtation with the quest for slots.