1972 Major League Baseball season

The 1972 major league baseball season was originally scheduled to begin on April 5. The 1972 strike caused the season to see its first 10 days of games canceled, resulting in the season starting on April 15, while the regular season ended as originally scheduled on October 4. The postseason began on October 7. The 69th World Series began with Game 1 with the Oakland Athletics of the American League defeating the Cincinnati Reds of the National League, four games to three, capturing their sixth championship in franchise history (and first in Oakland), since their previous in Philadelphia in 1930. This was the first of three straight victories behind the bats of Reggie Jackson and Bert Campaneris, and the pitching cadre of Catfish Hunter, Rollie Fingers, and Vida Blue. Jackie Robinson, the player instrumental in breaking the AL and NL's color barrier, threw out the first pitch prior to Game 2 in what would be his last public appearance. He died two days after the series ended at age 53 due to complications from diabetes and heart failure. Going into the season, the defending World Series champions were the Pittsburgh Pirates from the 1971 season. The season was the first to have games canceled by a player strike. It was also the last season in which American League pitchers would hit for themselves on a regular basis; the designated hitter rule would go into effect the following season.

The 43rd Major League Baseball All-Star Game, was held on July 25 at Atlanta Stadium in Atlanta, Georgia, home of the Atlanta Braves. The National League won in ten innings, 4–3, and was the first win in what would be a ten-win streak that lasted until 1983.

1972 marked the first year for the Texas Rangers, who had moved to Arlington, Texas from Washington, D.C. (where they played as the Washington Senators) after the 1971 season. The team was one of the worst ever fielded by the franchise, losing 100 games for the first time since 1964. Manager Ted Williams hated it in the Dallas–Fort Worth area, and resigned at the end of the season. Washington, D.C. was left without a major-league team for the first time since 1890. The city would not see a home team for 33 seasons, until the Montreal Expos relocated and became the Washington Nationals in 2005.

The Rangers' relocation necessitated the American League to transfer the team to the American League West division from the American League East division due to its distance from AL East teams. Because of this, one of the teams already in the AL West needed to switch to the AL East. The Chicago White Sox and Milwaukee Brewers were seen as the likeliest candidates to transfer divisions, although the Minnesota Twins lobbied to keep the Rangers in the East because it wanted both the Brewers and White Sox as division rivals. Even though the White Sox were slightly further east, it was decided that the Brewers, as the newer franchise, would make the move, even though the White Sox wanted to go to the East since five of the league's original franchises were in that division, and that the Cubs were in the National League East. The Brewers would become division rivals of the Twins and White Sox in 1994 with the formation of the American League Central, but this would last only through 1997, when Milwaukee transferred to the National League and became a division rival of the Cubs (the Brewers and Twins continue to face each other every year through interleague play).

1972 would also mark the Kansas City Royals' final year at Kansas City Municipal Stadium, as the next year they would move to Royals Stadium at the Truman Sports Complex in eastern Kansas City. The Royals had hoped to move out of Municipal after the 1971 season, but a series of labor strikes forced the team to spend one more year at the old facility, which hosted the Athletics from 1955–1967 (and the National Football League's Chiefs from 1963–1971).

The year ended on a sad note when Roberto Clemente died in an airplane crash off the coast of San Juan, Puerto Rico, on New Year's Eve, while participating in aid efforts after the 1972 Nicaragua earthquake.