The Baltimore Orioles have announced that outfielder Lee Lacy will undergo surgery to correct ligament damage to his right thumb and will be sidelined for about five weeks.

Lacy, an expensive free agent signed by the Orioles this winter after playing out his Pittsburgh Pirates contract, was hurt diving for a ball in the outfield at the Miami training base March 12. He was not believed seriously injured at the time, continued to play and was the Orioles' leading hitter this spring with a .341 average in 15 exhibition games.

When the pain persisted, Lacy was sent to Baltimore for an examination by a hand specialist. Placed on the 21-day disabled list, he will be operated on Wednesday and is not expected to return to the active roster until mid-May . . .

Glenn Hubbard's bases-full double off Mike Boddicker in the second inning staked a split squad from Atlanta to a three-run lead and the Braves beat Baltimore, 4-2, in yesterday's exhibition at West Palm Beach, Fla.

Len Barker won despite walking five Orioles and throwing three wild pitches in 3 2/3 innings. The Baltimore runs, unearned, came in the fourth on walks to Eddie Murray and Fred Lynn, a two-out throwing error by third baseman Bob Horner and a single by Boddicker, who, of course, won't get to bat in the American League regular season.

Horner got his first hit of the spring, a single up the middle in the sixth, after telling Manager Eddie Haas he doesn't need to go on the disabled list but feels he can be in the opening day lineup against Philadelphia. Horner is recovering from surgery to repair a broken right wrist . . .

Right-hander Steve Farr, the southern Marylander who was 3-11 with a 4.58 earned run average for Cleveland in 1984 after long persevering in the minors, was released by the Indians yesterday . . .

Reggie Jackson got into a fight Saturday morning in the parking lot of the Gene Autry Hotel near the Angels' Palm Springs, Calif., training camp. Police said he slapped one of two men who allegedly insulted him with racial slurs, and one of the men swung a tire iron, barely missing the baseball star.

Jackson told officers when he first saw the men driving on the sidewalks of the hotel complex he took down the car's license number and called police. During a second encounter minutes later, the men began heckling him and, as the confrontation developed, Jackson was helped by bystanders to hold the pair until officers arrived.

One man, age 20, was arrested on suspicion of assault with a deadly weapon; the other, 23, on a citation of disturbing the peace . . .

Mickey Mantle, back in baseball's good graces, has been named by the New York Yankees to throw out the ceremonial first ball at their home opener, April 16.