Bob Shawkey, a star pitcher for the New York Yankees when they began to dominate baseball in the 1920's, died New Year's Eve at the Veterans Administration Hospital in Syracuse after a long illness. He was 90 years old.

Shawkey, who won 198 games in the major leagues, also pitched for the Philadelphia Athletics, serving under Manager Connie Mack. With the Yankees, Shawkey pitched for Miller Huggins, whom he later succeeded as manager.

In 1923, Huggins named Shawkey to pitch the first game ever played at Yankee Stadium. In 1976, he threw out the ceremonial first ball at the renovated Yankee Stadium.

Robert John Shawkey was born Dec. 4, 1890, in Segal, Pa., and was almost 21 years old before breaking into professional baseball. He began his career with Harrisburg (Pa.) of the Tri-State League in 1911, where his record as a right-handed pitcher earned him a tryout with Connie Mack's Philadelphia Athletics. He did not become a regular until 1913 and two years later was picked up by the Yankees on waivers.

Upon returning from a year of naval service after World War I, he was given the nickname Bob the Gob, and helped the Yankees win their first pennant in 1921.

He pitched in New York for 12 years and had four seasons of 20 or more victories. He pitched in five World Series, one with the Athletics and four with the Yankees. His major-league record totaled 198 victories and 150 losses, with an earned run average of 3.09. Managed Yanks in 1930

His pitching career came to an end in 1928, but two years later, he was made manager of the Yankees following the death of Huggins, who had led the Yankees to six pennants and three World Series championships in nine years at the helm. Shawkey lasted just one season, guiding the Yanks to a third-place finish in the American League.

For a time, Shawkey managed in the minor leagues, first with Jersey City in the International League, then with Scranton and finally with Newark, the Yankees' top farm club. Later, he became baseball coach at Dartmouth College.

''I didn't expect to play ball for a living at all when I was a youngster,'' he once told Harold C. Burr, a writer for The Brooklyn Eagle. ''But I guess nature took its course. I started out as a first baseman, but I could always throw the ball hard.''

Mr. Shawkey said he could never forget his first start on the mound for Connie Mack in a practice game. ''I was wild as a mountain goat,'' he said, ''and my fastball was whistling by the ears and ankles of the batters, while my curve kept breaking into the dirt. Then I lost my temper, and Mr. Mack waved me out.

''After I cooled off a bit, I asked Chief Bender to show me what was wrong with my curve. 'Sure,' said the Chief, 'I'll show you anything, but first you will have to show me that you can control yourself and also that ball. Never mind your smoke or curve. Learn to put that ball where you want it. Then come to me and I'll show you how to put stuff on it.''' Praise for Mack and Huggins

Mr. Shawkey felt that the Athletics' ball clubs of 1913-14 were the smartest teams he had ever seen. He regarded Huggins as the shrewdest manager. ''I started under Mack and finished under Huggins,'' he said. ''Those were two wonderful breaks in my favor.''

James Shawkey