If you listen to Baltimore Orioles games, then you're painfully familiar with baseball's good news-bad news broadcasting team of Jon Miller and Tom Marr.

The good news is Miller, one of sportscasting's more inventive minds, full of stories and relaxed banter. The bad news is Marr, one of sportscasting's more boorish nightmares, full of hysteria and homerisms.

Enter Bob Costas, NBC Sports' rising young star and acknowledged baseball buff. When his contract runs out in May 1986, Costas might ask NBC to include in any new agreement the right to do baseball play-by-play on radio.

If Orioles fans are lucky, they could have a Costas-Miller team for the 1987 season, and Marr, justifiably, would have to pay his way into Memorial Stadium.

Costas, who hosts NBC's NFL pregame show and does play-by-play on the network's backup baseball telecast, said: "It's possible I'll make as a point of the (contract) negotiations that I do baseball whenever possible.

"I'd like to do radio in the near future," he said. "It doesn't mean 1985. It does mean before the decade is out. The main thing for me is to become the best baseball announcer that I can."

Costas already is a fine baseball broadcaster, partly because of his passion for the game. And, like Miller, he prefers radio to television.

"There'a romance and mystique to radio that TV can't match," Costas said. "Baseball's a day-to-day game. The day-to-day rhythm is part of the game. I miss that, and I can't get that without being with one club every day.

"It's the greatest hanging-around game ever invented. You hang around the batting cage, in hotel lounges or bars after the game, talking to baseball people.

"You go into towns a few days at a time. There's no hanging around football. You go into town on Saturday, check into the hotel, get room service, wake up Sunday morning and go to the stadium."

The question of whether Costas woule be able to work baseball on radio -- and in Baltimore, in particular -- is hard to answer. Network obligations take priority, of course, and NBC understandably doesn't like its top talents moonlighting.

But other NBC stars -- Dick Enberg, Vin Scully and Tony Kubek, for instance -- do some baseball for local radio and television, and Marv Albert still does the New York Knicks and Rangers.

With a team such as the Orioles, Costas probably could work 100 games or so into his schedule, and a third broadcaster could fill in, similar to when Marr broke in with Chuck Thompson and the late Bill O'Donnell in 1979.

Perhaps most critical to this pipe dream of a Costas-Miller pairing: would WFBR, the Orioles' flagship station, be interested in Costas, and would Costas be interested in Baltimore?

"I doubt we could afford him," said Harry Shriver, WFBR's general manager, "but we'd certainly be interested in talking to him. He's tremendous. He does a hell of a job on TV."

As for Costas, one of his baseball charms is his contention that four criteria must be met by a franchise before he would broadcast there.

"If I were fortunate enough to be asked," Costas said, "I'd consider teams with 1) some kind of tradition, 2) in good baseball cities, 3) in real ball parks with real grass and 4) where radio still has some type of importance in the city."

That seemingly qualifies Baltimore, which, as Miller pointed out, "doesn't have the tradition Boston has, but it has very good tradition."

Miller and Marr are under contract with WFBR through the 1986 season. As unlikely as it may seem, it's possible that the 33-year-old Miller and the 32-year-old Costas could be paired by 1987 -- sort of like having Ripken and Murray bat 3-4 in your lineup.

Until then, or maybe longer, we'll still have Tom Marr to tolerate. Maybe not. You know how some folks, while watching games on TV, turn the sound down? When Marr does baseball, it's the only time you'd want to have a game on the radio with the sound turned down.

CBS' Billy Packer, who will join Brent Musburger on Saturday's Georgetown-St. John's basketball telecast, says the Big East has more top-notch teams than any other conference in the nation, but that the ACC has the best balance.

"If you threw out the bottom two teams from the Big Ten," Packer says, "then they'd be the best from top to bottom."

Of Georgetown, Packer says, "They're not invincible. Several teams in the country could beat them. But if I were a coach, give me Georgetown and I'll take my chances on winning a national championship with that team."