This was the final season the majority of MLB teams wore wool flannel uniforms. The Pirates and Cardinals wore double knit uniforms of nylon and rayon throughout 1971, and the Orioles gradually phased out flannels, going all-double knit in time for the ALCS. By 1973, flannel uniforms completely disappeared from the MLB scene.
Three of the four division races were anticlimactic; the only race was in the N.L. West between old rivals Los Angeles Dodgers and San Francisco Giants. The Giants led by 8.5 games on September 1 but the Dodgers chipped away. In mid September, the Dodgers won 8 in a row, including 5 over the Giants to narrow the gap to one game. But they could get no closer; ultimately both teams won on the final day of the season and the Giants won the division by 1 game.
February 9 – Former Negro leagues pitcher Satchel Paige is nominated for the Hall of Fame. On June 10, the Hall's new Veterans Committee formally selected Paige for induction.
March 7 - The Milwaukee Brewers and Oakland Athletics play a spring training game where only three balls are needed for a walk. The Athletics won 13–9, with the game featuring 19 walks. The experiment is not tried again.[78]
April 6 – Bill White, a former NL first baseman, became the first African-American to do play-by-play as part of a regular broadcast crew of a team, when the New York Yankees opened the season with a game in Boston.
June 23 – In a singular performance, pitcher Rick Wise of the Philadelphia Phillies no-hits the Reds, 4–0, and bangs two home runs in the game. Wise joins Earl Wilson and Wes Ferrell as the only pitchers to pitch a no-hitter and hit a home run in the same game. It is the second no-hitter against Cincinnati this month, both in Riverfront Stadium.
July 7 – Commissioner Kuhn announces that players from the Negro leagues elected to the Hall of Fame will be given full membership in the museum. It had been previously announced that they would be honored in a separate wing.
July 9 – The Oakland Athletics beat the California Angels 1–0 in 20 innings – the longest shutout in American League history. Vida Blue strikes out 17 batters in 11 innings for Oakland, while the Angels' Billy Cowan ties a major league record by fanning six times. Both teams combine for 43 strikeouts, a new major league record.
August 14 – Ten days after his 200th victory, St. Louis Cardinal pitcher Bob Gibsonno-hits the Pittsburgh Pirates 11–0, the first no-hitter ever pitched at Three Rivers Stadium. He strikes out 10 batters along the way; three of those are to Willie Stargell, including the final out. The no-hitter is the first to be pitched in Pittsburgh in 64 years; none had been pitched in the 62-year (mid-1909 to mid-1970) history of Three Rivers Stadium's predecessor, Forbes Field.
August 28 – Phillies pitcher Rick Wise hits two home runs, including a grand slam off Don McMahon, in the second game of a doubleheader, duplicating his feat in his June no-hitter. Wise beats the Giants 7–3.
September 30 – The Washington Senators' lead 7–5 in their last home game, but forfeit the game to the New York Yankees, when, with two outs in the top of the ninth, fans storm the field. The Senators moved to Dallas, Texas, and became the Texas Rangers for the 1972 season, leaving the Nation's Capital without an MLB team until 2005.
October 17 – Pitcher Steve Blass throws a four-hitter and Roberto Clemente homers as the Pittsburgh Pirates win Game Seven of the World Series over the Baltimore Orioles, 2–1, becoming World Champions for the first time since 1960. Clemente is named the Series MVP. Game Four of this World Series was the first night game played in Series history.
November 2 – The Orioles' Pat Dobson pitches a no-hitter against the Yomiuri Giants, winning 2–0. It is the first no-hitter in Japanese-American baseball exhibition history. The Orioles compile a record of 12–2–4 on the tour.
