Eddie Yost, the Washington Senators’ third baseman of the 1950s whose extraordinary ability to coax walks made him a pest to opposing pitchers and an anomaly in baseball history, died Oct. 16 at an assisted-living facility in Weston, Mass. He was 86.

His daughter Felita Yost Carr confirmed his death but could not cite a specific cause, other than a “bad heart.”

Mr. Yost, who first joined the Senators as a 17-year-old in 1944, became one of the most popular players on a team with a hopeless record of futility. During his 12 seasons as the starting third baseman from 1947 through 1958, the team had a winning record only one time.

But, along with hitters Mickey Vernon and Roy Sievers, Mr. Yost was a rare bright spot for the Nats, as the team was often called.

Although Mr. Yost compiled a mediocre lifetime batting average of only .254, his uncanny batting eye enabled him to draw walks almost at will, earning him the nickname “The Walking Man.” One opposing manager fined his pitchers $25 for each walk given up to Mr. Yost but had to stop the practice when his pitching staff ended up hundreds of dollars in debt.

“He reached the point where the umpires said if he didn’t swing at a pitch, they wouldn’t call it a strike,” said Phil Wood, a longtime Washington broadcaster and baseball historian.

Mr. Yost led the American League in walks six times and had eight seasons with more than 100 walks. By contrast, no member of the 2012 Washington Nationals had more than 67 walks.

His ability to draw walks and score runs — and to avoid swinging at bad pitches — was not always appreciated in his time. When Mr. Yost retired in 1961, his 1,614 walks ranked fourth in baseball history, after Hall of Fame sluggers Babe Ruth, Ted Williams and Mel Ott. Mr. Yost is now 11th on the all-time list.

After Mr. Yost’s only All-Star season in 1952, Senators owner Clark Griffith said, “I wouldn’t swap him for Mickey Mantle straight up, and to prove it, I’m paying him almost twice as much as the Yankees are paying Mantle.”

Washington’s cavernous Griffith Stadium, with its 400-foot left-field foul line, greatly reduced the power numbers of the right-handed-hitting Mr. Yost. Through the 1953 season, he had hit 55 home runs — 52 of them on the road.

His 28 home runs while leading off games were a major league record until broken by Bobby Bonds in the 1970s and later by Rickey Henderson.

Edward Frederick Yost was born Oct. 13, 1926, in Brooklyn and played baseball and basketball at New York University before signing with the Nats in 1944. After two years in the Navy, he returned to the Nats in 1946 and never played in the minor leagues.

In the offseason, he attended NYU and received a master’s degree in physical education in 1953.

In Washington, Mr. Yost was the team’s iron man, playing in 829 consecutive games from 1949 to 1955, the most since Lou Gehrig’s then-record 2,130-game streak ended in 1939. After the 1958 season, he was traded to the Detroit Tigers, then in 1961 joined the new Los Angeles Angels, becoming the first player to bat for the expansion team.

Mr. Yost succeeded Bob Feller as the American League’s player representative in the 1950s, testified before Congress on baseball’s antitrust exemption, and helped increase the minimum salary and pensions for players.

He later was the third-base coach for the Senators, New York Mets — including the World Series-winning “Miracle Mets” of 1969 — and Boston Red Sox. In retirement in Wellesley Hills, Mass., he enjoyed repairing clocks and carousel horses.

His wife of 45 years, Patricia Healy Yost, died in 2007. Survivors include three children, Felita Yost Carr of Hollis, N.H., Michael Yost of Huntington Beach, Calif., and Alexis Yost of Wellesley, Mass.; a sister; and two grandsons.

Mr. Yost’s career on-base percentage of .394 ranks higher than many players with gaudier batting averages, including Willie Mays, Hank Aaron, Honus Wagner and Pete Rose. His remarkable knack for drawing walks was a mystery that opposing pitchers never solved.

“Those pitchers aren’t walking me because they feel friendly toward me,” Mr. Yost told The Washington Post in 1953. “The opposite is more true. They’re careful not to lay them up there for me. They pitch to me like I’m a .400 hitter.”