MANAGUA, NICARAGUA, JAN. 30 -- The Sandinista government today released American pilot James Denby, suggesting he "go home to watch the Super Bowl" after his nearly eight-week detention here.

The 58-year-old Denby, from Carlinville, Ill., and a farm owner in Costa Rica, said the Sandinistas freed him after suggesting he go watch the championship football game. He was released into the custody of Bill Press, a California Democratic candidate for the U.S. Senate, and flown directly to Los Angeles on a private plane chartered by Press.

"He's an American. I'm an American. We wanted to get him back," said Press, explaining his role, at Sandino International Airport before departing.

Denby's small Cessna 172 airplane was shot down Dec. 6 by Sandinista Army troops just before it left Nicaraguan airspace for Costa Rica.

Denby said he had requested prior clearance to fly over Nicaragua from Belize en route to his Costa Rican farm, but Sandinista authorities said the permission was not granted.

Sandinista Defense Minister Humberto Ortega accused Denby of providing military logistical support to the U.S.-backed rebels, known as contras.

He was jailed for violating national security and faced a possible five- to 30-year sentence.

However, in an unexpected concession under the terms of a regional peace plan, President Daniel Ortega on Jan. 16 abolished the special tribunals for suspected contra collaborators where Denby was to be tried.

His case passed to the regular courts, where the rules of evidence are stricter and the government's conviction rates are lower.

A senior Sandinista official said earlier this week that the government lacked sufficient evidence to make a case against Denby in the regular courts.

Denby's brother, William, a lawyer, said his legal status was unclear because the Sandinista government said it would still press international charges against Denby here and abroad for allegedly aiding the contras from his farm.

The prosecutor had sought to build a case using a 1984 interview that Denby gave to a farming magazine in which he sympathized with the contra cause and said he had allowed them to use his ranch as a safe haven.

Denby also was a neighbor and associate of another American farmer in Costa Rica, John Hull, an outspoken and controversial contra supporter.

William Denby said his brother will be represented by Owyn Hodgson, his Nicaraguan lawyer, and by the Humanitarian Law Project of Los Angeles. The freed prisoner said he received "very good treatment" during his detention.

Press, a former television broadcaster in California and an opponent of U.S. aid for the contras, said he has been urging Sandinista officials during the past three weeks to free Denby before the U.S. Congress votes Tuesday and Wednesday on a Reagan administration request for $36 million in aid to the contras.

"My recommendation for people in Nicaragua was to send any signal they could for peace in Central America," Press said.