Elston Howard, the first black to play for the New York Yankees and a star with them for a decade, died early today after heart failure. The 1963 most valuable player in the American League was 51.

"Mr. Howard passed away at 12:25 a.m.," said a Columbia Presbyterian Hospital spokesman. "He had been here since Dec. 2. The cause of death has been listed as heart failure."

Mr. Howard, who suffered from heart disease for the past two years, was an administrative assistant to the Yankee's principal owner, George Steinbrenner, after having been a coach for 11 years. pHe quit coaching because of heart problems.

"We have lost a dear friend and vital part of our organization," said Steinbrenner. "If indeed humility is a trademark of many great men -- with that as a measure, Ellie was one of the truly great Yankees. A quiet man with friendship and caring for all . . . our lives are richer because he touched them."

When the Yankees hired Mr. Howard to coach Oct. 22, 1968, making him the first black coach in the American League, he said, "Some day, if I'm capable of managing, I might want to think it over. You have to learn. You see a lot of things as a catcher because everything is happening right in front of you."

Mr. Howard's best chance to become the first black manager in baseball came in 1973 when Ralph Houk shocked the Yankees by resigning.

"I'm ready," Mr. Howard said at the time. "They've got my number. I'll take it without question if they offer it to me."

The Yankees never made the offer.

Mr. Howard was a top catcher, making the AL All-Star team at the position nine times even though teammate Yogi Berra, a Hall of Fame catcher, also was selected six of those years. Mr. Howard also played outfield and first base.

Born in St. Louis Feb. 23, 1929, Mr. Howard came out of the old Negro League -- he once was a roommate of Hall of Famer Ernie Banks with the Kansas City Monarchs -- to break the color line with the Yankees in 1955, eight years after Jackie Robinson had become the first black in major league baseball.

Mr. Howard played for the Yankees until traded to Boston Aug. 3, 1967. He played with the Red Sox in 1968, then rejoined New York as a coach.

Mr. Howard had a batting average of .274 for 14 years, with 167 home runs and 762 runs batted in. In 1963, he hit .287, with 28 homers and 85 RBI. In 10 World Series he averaged .246, with five homers.

He balked at joining the Red Sox in 1967, but changed his mind after a personal phone call from club owner Tom Yawkey and participated in Boston's stretch drive to its first pennant in 21 years.

In 1968, he hit only .241 in 71 games and received the silent treatment from Manager Dick Williams. But Mr. Howard denied he had problems with Williams. "I never had a problem with any manager," he said.

Mr. Howard is survived also by his wife, Arlene, of Teaneck, N.J.; two daughters, Cheryl, an actress-singer, and Karen of Woods, Pa., and a son, Elston Jr., of Miami.

Private visitation will be held at the Frank Campbell Funeral Home in New York Monday evening. A funeral mass will be said Tuesday at 11 a.m. at the Riverside Church with burial at the George Washington Cemetery in Paramus, N.J.