July 22 – New York Metsthird basemanRay Knight incited a bench clearing brawl at Riverfront Stadium against his former teammates, the Cincinnati Reds.Eric Davis, pinch-running for Reds player/manager Pete Rose in the tenth inning, stole second and third base. Knight took the throw from Mets catcherGary Carter late, brought his glove to Davis' face and knocked his helmet off. A stare-off ensued, followed by a right cross from Knight. The benches emptied and as a result of all the ejections from this fight, Mets manager brought back-up catcher Ed Hearn into the game, and moved Carter from behind the plate to third. Roger McDowell replaced Jesse Orosco on the mound, and Orosco went into right field. They traded positions with two outs in the eleventh, and McDowell traded positions with left fielderMookie Wilson with one out in the 12th. This rotation continued for the remainder of the game, which the Mets won in fourteen innings.
July 29 – Sparky Anderson of the Detroit Tigers becomes the first in baseball to achieve 600 career wins as a manager in both the American and National League.
August 11 – Cincinnati player-manager Pete Rose, 45, singled four times and doubled to set an NL record with the 10th five-hit game of his career. Rose drove in three runs in a 13-4 loss to the San Francisco Giants, to move one ahead of Max Carey for the record.
August 12 – Don Baylor of the Boston Red Sox set an AL record when he was hit by a pitch for the 25th time that season, breaking the record he shared with Bill Freehan (1968) and Norm Elberfield (1911). Kansas City's Bud Black was the pitcher as the Royals completed a doubleheader sweep with a 6-5 victory.
August 14 – Pete Rose enjoys a 3-for-4 day, the last hit being the 4,256th and final hit of his career.
August 17 – Pete Rose inserts himself in as a pinch hitter, and takes a called third strike from San Diego Padres pitcher Goose Gossage to end a 9-5 loss for the Cincinnati Reds. It is Rose's final plate appearance (15,890), at-bat (14,503), and game (3,562), all of which are Major League career records.
September 3 – Billy Hatcher hit a home run in the top of the 18th inning to give the Houston Astros an 8-7 victory over the Chicago Cubs. The two teams began with 14 innings one day earlier, and use a major league record 53 players in the game.
September 17 – The New York Mets secure the National League East title with a 4-2 win over the visiting Chicago Cubs, their 95th victory of the year. The team would finish the season at 108-54, the best record of any team during the 1980s.
October 12 – In Game 5 of the American League Championship Series, the Boston Red Sox, trailing 3 games to 1 to the California Angels and one out away from elimination, are rescued when Don Baylor delivers a two-run home run to trim the Angel lead from 5-2 to 5-4. Then, with Rich Gedman running on first, and one strike away from elimination, Dave Henderson crushes a pitch from California's Donnie Moore into the center field stands for a 6-5 lead. The Red Sox win 7-6 in extra innings and extend the series to another game.
October 15 – In the longest game in post-season history (until the 2005 National League Division Series), the Mets beat the Astros 7–6 in 16 innings to earn their first trip to the World Series since 1973. New York scores three runs in the top of the 9th to force extra innings. The Mets score three more runs in the top of the 16th, and Houston answers with two of its own before Jesse Orosco fans Kevin Bass to end the game.
October 25 – With the Red Sox leading 5-3 in Game 6 of the World Series, and just one out away from winning their first championship since 1918, the Red Sox give up hits to Gary Carter, Kevin Mitchell and Ray Knight, and pitcher Bob Stanley throws a wild pitch that allows Mitchell to score. Then Mookie Wilson hits a slow grounder that keeps bouncing, right between the legs of first baseman Bill Buckner, allowing Knight to score to give the New York Mets an improbable 6-5 win. Boston's Calvin Schiraldi absorbs the loss.
November 12 – Roger Clemens of the Boston Red Sox wins the American League Cy Young Award unanimously, joining Denny McLain (1968) as the only pitchers to do so. Clemens finished with a 24-4 record with 238 strikeouts and a 2.48 ERA.
The Minnesota Twins announce interim manager Tom Kelly will be their new skipper for the 1987 season. Kelly, who replaced Ray Miller late in the season, will compile a losing record (1140–1244) but wins two World Championships during his 16-year tenure as the Twins manager.
St. Louis Cardinals reliever Todd Worrell, who led the National League with 36 saves, receives the Rookie of the Year honors. Worrell had helped St. Louis to the 1985 World Series as a late-season call-up but was still a rookie the next season as defined by the BBWAA.
January 2 – Bill Veeck, 71, executive who owned the Cleveland Indians, St. Louis Browns and Chicago White Sox; helped break the American League's color barrier by signing Larry Doby in 1947 and was the last owner to bring Cleveland a World Series title in 1948, though he is perhaps best remembered for the wacky promotions he used to draw crowds and entertain fans at the ballpark, which included using midget Eddie Gaedel in a 1951 game, and installing fireworks in the Comiskey Park scoreboard.
January 13 – Mike Garcia, 62, All-Star pitcher who won 142 games for the Cleveland Indians, winning 20 games and leading the AL in ERA twice each; member of the Indians' "Big Four", along with Bob Feller, Bob Lemon and Early Wynn.
January 15 – Fred Thomas, 93, third baseman for three American League teams, a member of the champion Red Sox in the 1918 World Series and a World War I veteran.
February 17 – Red Ruffing, 80, Hall of Fame pitcher whose 273 victories included four straight 20-win seasons for the Yankees from 1936–1939, with seven World Series victories helping the team win six championships; batted .300 eight times, and was later a minor league manager.
May 4 – Paul Richards, 77, manager and executive, formerly a catcher, who built the Baltimore Orioles team that later dominated the AL in the late 1960s and early 1970s, and also managed the White Sox and served as an executive for the Astros and Braves.
July 2 – Peanuts Lowrey, 68, All-Star outfielder, mainly with the Chicago Cubs and St. Louis Cardinals, who batted .310 in the 1945 World Series.
July 3 – Bill McCahan, 65, pitcher for the 1946-49 Philadelphia Athletics, who threw a no-hitter game in 1947.
July 8 – Johnny Cooney, 85, pitcher/outfielder/first baseman for the Boston Bees/Braves, Brooklyn Dodgers and New York Yankees between 1921 and 1944, later a longtime coach.
July 9 – Red Lucas, 84, pitcher who won over 150 games for the Cincinnati Reds and Pittsburgh Pirates; had 27 consecutive complete games in 1931–1932 and set record with 114 career pinch hits.
July 25 – Ted Lyons, 85, Hall of Fame pitcher who played his entire 21-year career with the Chicago White Sox, collecting 260 victories; led AL in wins, innings, complete games and shutouts twice each, and won 22 games for 62-92 team in 1930.
September 4 – Hank Greenberg, 75, Hall of Fame first baseman and left fielder for the Detroit Tigers who won MVP awards at both positions; career .313 hitter led the American League in home runs and RBI four times each despite losing four and a half seasons to military service; 58 homers in 1938 shared record for right-handed batters; first Jewish player elected to Hall of Fame.
December 8 – Pip Koehler, 84, utility man for the 1925 New York Giants.
December 10 – Si Burick, 77, sportswriter for the Dayton Daily News since 1928, who covered the Cincinnati Reds and became the first writer from a non-major league city to be honored by the Hall of Fame.
December 12 – Johnny Wyrostek, 67, All-Star outfielder for the Philadelphia Phillies and Cincinnati Reds.
December 19 – Al Stokes, 86, catcher who played from 1925 to 1926 for the Boston Red Sox.