The Baltimore Orioles lost their four-year gamble on outfielder Dan Ford, 33, by putting him on waivers yesterday. If no team claims him, he will be released.

The team's general manager, Hank Peters, explained: "The physical problems Dan has experienced with his knees made him available to use only on a limited basis, if at all. For that reason, he didn't fit into our plans for the upcoming season."

The Orioles got him from the California Angels Jan. 28, 1982, for third baseman Doug DeCinces and pitcher Jeff Schneider. It was a gamble for both teams; the Angels knew about DeCinces' bad back and the Orioles knew Ford's right knee, operated on in November 1979, wasn't right.

With the Orioles, he was on the disabled list four times, playing 302 of 647 games. He first hurt his left knee in 1983. Last year, after hitting .189 with one homer and one RBI in 28 games, he had his fourth knee operation, this time on the left one.

The Orioles, who have a reputation for canny deals, lost this one. In 1982, DeCinces hit .301 with 30 homers and 97 RBI in 152 games. Last season, it was .244, 20 and 78 in 120 . . .

Baseball's drug trials ended in Pittsburgh when Jeffrey Lynn Mosco, 30, pleaded guilty to three counts of selling cocaine to John Milner.

Rod Scurry, Lee Lacy, Dale Berra and Milner, all former Pirates, were just about to testify when Mosco and prosecutors struck a plea bargain. Eight other counts were dropped. The other six defendants in the series of trials are in federal prison.