April 13 – Philadelphia Phillies catcherBo Díaz accomplishes something that only 11 other Major League players have in the 150-plus year history of the sport: a "Sayonara Slam" (a walk off Grand Slam in the bottom of the ninth inning with two outs and his team trailing by three runs). With the New York Mets leading the Phillies, 9–6, and the Phillies down to their last out, Díaz drives a 2-1 Neil Allen pitch out of Veterans Stadium to win the game for the Phillies, 10–9.
May 2 – José Oquendo makes his major league debut with the New York Mets. Having been born on July 4, 1963, he is the first player in franchise history to be younger than the franchise (which began play in 1962).
July 24 – In the game now known as the Pine Tar Game, George Brett hits an apparent go-ahead 2-run home run off of Goose Gossage in the ninth inning of a game against the New York Yankees at Yankee Stadium. However, Yankees manager Billy Martin challenges that Brett's bat has more than the 18 inches (460 mm) of pine tar allowed, and home plate umpire Tim McClelland upholds Martin's challenge. After being called out and having the home run nullified, Brett goes ballistic and charges out of the dugout after McClelland. The AL president's office later upholds the Kansas City Royals protest, restoring the home run, and the game is completed on August 18, with the Royals winning 5-4.
September 17 – The Chicago White Sox defeat the Seattle Mariners 4-3 at old Comiskey Park, clinching their first division title. It secures their first post season birth since 1959, and the last the team has at old Comiskey.
October 2 – Inspired by the outpouring of tributes lavished on retiring Boston Red Sox star Carl Yastrzemski, the producers of Boston phone-in radio show The Sports Huddle on radio station WHDH, decide to do a satirical tribute to Vern Rapp, who also plans to retire at the end of the season after five years as first-base coach of the Montreal Expos (1979-1983). On the last day of the regular season, they proceeded with their tongue in cheek tribute to Rapp, including a mock telethon in which phone callers were invited to pledge money to Rapp's retirement fund (a substantial sum was actually pledged, though no money was collected), and a song to the tune of Bye Bye Birdie ("Bye Bye Vern Rapp"). The program turned out to be anything but a spoof, though. St. Louis Cardinals broadcaster Mike Shannon spoke admiringly of the man, and Rapp, reached by telephone in Montreal, was choked up by the whole affair. WHDH also conducted a telephone interview with Sheldon Bender, vice-president of player personnel for the Cincinnati Reds. Until the station called, Bender was unaware that Rapp was leaving the Expos. Bender suggested Rapp at a meeting the next day at which the Reds' bosses were discussing whether to fire Manager Russ Nixon. One thing led to another, and Rapp received a surprise phone call from Bob Howsam, who had returned from his own retirement to try to arrest the declining fortunes of the Reds. Rapp decided that becoming the Reds' skipper was worth unretiring for, and accepted the job on October 5. WHDH sent Rapp the cassette recording of what turned out to be a most momentous broadcast. Bender admitted "Vern wasn't a candidate for the job until the station called."
October 30 – Boston Red Sox farmhands John Mitchell, Anthony Latham and Scott Skripko, are deep-sea fishing off the coast of Florida when their boat capsizes. Boat owner Mark Zastrowmy and Latham drown. Skripko and Mitchell survive over 20 hours in the water by clinging to debris; Skripko holds onto a cooler for 20 hours and Mitchell a bucket for 22 hours.
March 12 – Bob Hall, 59, pitcher for the Boston Braves (1949–50) and Pittsburgh Pirates (1953).
March 30 – Joe Cicero, 72, outfielder for the Boston Red Sox and Philadelphia Athletics.
April 9 – Bill Kennedy, 62, pitcher for the Indians, Browns, White Sox, Red Sox and Redlegs from 1948 to 1957.
April 11 – Mike Menosky, 88, outfielder for the Pittsburgh Rebels, Washington Senators and Boston Red Sox between 1914 and 1923.
April 12 – Carl Morton, 39, pitcher with the Montréal Expos and Atlanta Braves, who was named the National League Rookie of the Year in 1970.
April 17 – Dutch Leonard, 74, five-time All-Star pitcher who employed the knuckleball in earning 191 wins over 20 seasons.
April 18 – Woody Rich, 77, pitcher for the Red Sox and Braves Boston teams between 1939 and 1944.
April 25 – Carlos Paula, 55, Cuban outfielder, first black player in Washington Senators history.
July 7 – Vic Wertz, 58, All-Star right fielder and first baseman for five AL teams who had five 100-RBI seasons, but was best remembered for the fly ball caught spectacularly by Willie Mays in the 1954 World Series.
August 16 – Earl Averill, 81, Hall of Fame center fielder for the Cleveland Indians who batted .318 lifetime and had five 100-RBI seasons; his line drive off Dizzy Dean's foot in the 1937 All-Star game led to the end of Dean's career.