Abner Doubleday -- as everybody grew up believing, anyway -- invented baseball and now his great-great-nephew has announced that his corporation has agreed to buy controlling interest in a major-league team: the New York Mets. His name is Nelson Doubleday, president of Doubleday and Co., the publishing firm, that joins with City Investing Co., an oldline New York firm, and Fred Wilpon, chairman of the board of Sterling Equities, Manhasset, N.Y., in an approximately $21 million deal. The club is being unloaded by Joan Whitney Payson's widower, Charles Shipman Payson, and daughter, Lorinda de Roulet, who saw the Mets go downhill in several directions the past couple of years . . .

Another Maryland face in a new place: Mark Manges, former Terp stalwart, huddled lately with Philadelphia Coach Dick Vermeil about a shot at joining the Eagle quarterback corps now that backup John Walton has quit to coach Elizabeth City State. Vermeil also interviewing ex-Colt Mike Kirkland and former USC passer ron Hertel and says, "I may sign all three or maybe just two" . . .

Killed in a car-truck collision this month: Eagle fans' favorite Liberty Belle cheerleader, Cheryl Frey, 25 . . .

One who might have graced the Super Bowl but for Dallas 35-34: Maureen Callahan of Silver Spring. She made the cheerleading squad of Redskinettes '79, going through all the rigorous tryouts and never missing a step. It was midseason before Redskinette directors knew she was legally blind -- since losing all but a bit of peripheral vision to a cure-unknown disease three years ago. The Monday Morning QB Club surprised her with an award last month.