Georgetown's basketball team will play Virginia at Capital Centre on the night of Dec. 11 in a game that represents a major breakthrough for cable television sports programming.

According to sources, the game will be televised in prime time by Ted Turner's Atlanta super station WTBS-17, owned by the Turner Broadcasting System and available to 21 million cable television subscribers around the country. The agreement will be announced at a press conference here today at 2 p.m.

With the exception of several areas in Northern Virginia, most of the Washington area is not wired for cable television.

Rex Lardner, director of sports programming at CBS, said yesterday that the agreement represents the first time a cable network had outbid the major networks for rights to a significant sporting event other than boxing.

"I just heard from (Georgetown Athletic Director) Frank Rienzo that they have decided, but it's not CBS . . . He's going to go with another bidder. I assume it's Ted Turner. My understanding is there's no cable in Washington. Maybe it's a combination of cable and closed circuit. I just don't know."

Neither Rienzo or Richard Schultz, the Virginia athletic director, could be reached for comment. Officials at WTBS declined to comment.

CBS television had wanted to broadcast the game on Jan. 8 in prime time after an NFL playoff game. Network sources say bidding for the game reached the $500,000 range.

According to Alan Baker, vice president for press information at NBC, the network was interested in broadcasting the game but had a conflict on Dec. 11 because of a committment to broadcast the Illinois-Kentucky game that afternoon. Baker said he was not sure whether NBC made a dollar offer for the game.

Both NBC and CBS televise regular-season NCAA games. CBS is entering the second of a four-year contract for the NCAA playoffs and championships.

"It's the first time, it's a major event not including boxing that he's (Turner) doing live," Lardner said. "It seems to me it's the first step to pay cable. He reaches about 25 million people total. The networks reach over 80 million. I am really, really depressed about it. We really wanted it. It has the potential to be the best regular-season college match-up in 10 years."

Baker agreed that the telecast would be "the biggest thing cable has done in sports."

Asked if he thought the agreement was a mistake, Lardner said, "I do. A lot of people won't be able to watch it. We could have promoted it in a much larger fashion. We were going to work it out to both conferences' advantage. It would have been something very special for everybody."

Virginia finished the 1982 season as the No. 3-ranked team.

The game also will mark the first meeting between the schools' dominant centers, Virginia's Ralph Sampson and Georgetown's Patrick Ewing.