1873 in baseball

• National Association: Boston Base Ball Club

• Boston Red Stockings second baseman Ross Barnes leads the NA with 138 hits, 43 stolen bases, 125 runs scored, a .431 batting average, a 1.080 OPS, and a 207 OPS+.^[1][2]
• Boston Red Stockings pitcher Al Spalding has a record of 41–14, leading the NA with 41 wins and 496.2 innings pitched. His 50 strikeouts rank second in the league. He has a 2.99 earned run average and a 115 ERA+.^[3][4]

January–March edit

• March 3 – For the first time, the NA adopts a standardized ball to be used in all league games.

April–June edit

• May 14 – Nearly 5,000 fans watch the upstart Philadelphia Club defeat the established Athletics 5–4 in 13 innings. Only once before, in 1865, had that many innings been played in one game.
• June 7 – Mutual and Philadelphia combine for 40 errors. The Philadelphias, aided by the Mutuals' 26 miscues, win 12–10.
• June 11 – 10,000 fans are in attendance see Philadelphia score 5 runs in the 7th inning to defeat Athletic 7–5.

July–September edit

• July 4 – Leading 11–3 over Resolute of Elizabeth, the Bostons score 21 runs in the bottom of the 9th inning for a 32–3 victory. The home-ahead rule would not be instituted for 6 more years.
• July 22 – Tom Barlow of Atlantic lays down 6 bunts, all for hits, in a game against Lord Baltimore.
• July 24 – Bob Ferguson of the Atlantic is the umpire in a game between Mutual of New York and Lord Baltimore which ends with the Mutuals scoring 3 runs in the bottom of the 9th for an 11–10 victory. Ferguson and Mutual's Nat Hicks get into an altercation with Ferguson breaking Hicks' arm by hitting him with a bat. Ferguson requires a police escort to leave the field and Hicks will be out for 2 months due to the incident.
• August 16 – Boston defeats Philadelphia 11–8 in Chicago in front of several thousand fans. After the game, it is announced that Chicago has signed several players in hopes of placing a team in the NA for the 1874 season.

October–December edit

• October 16 – Lord Baltimore turns a triple play in a losing cause against Philadelphia.
• October 22 – Boston wins the pennant for the 2nd year in a row. They clinch on the same date as they had in 1872.
• November 6 – A crosstown benefit game is played between the Philadelphia and Athletic Clubs under a proposed rule of 10 men on the field and 10 innings for a game. The extra player is placed on the infield as a right shortstop and with most observers feeling the extra player unnecessary, the rule is never implemented.

• January 10 – Chick Stahl
• January 10 – Jack O'Neill
• January 19 – Arlie Pond
• January 23 – Red Donahue
• February 5 – Jack O'Brien
• February 20 – Tom O'Brien
• March 10 – Gene DeMontreville
• March 29 – Duff Cooley
• April 7 – John McGraw
• April 22 – Frank Figgemeier
• May 23 – "Brewery" Jack Taylor
• June 13 – Walter Coleman
• July 11 – Jimmy Slagle
• July 19 – Harry Davis
• August 26 – Chick Fraser
• October 5 – Claude Ritchey
• October 9 – Bill Reidy
• November 4 – Bobby Wallace
• November 10 – Willie McGill
• November 24 – Ed Doheny
• November 29 – Jake Weimer
• December 6 – Harry Wolverton
• December 9 – Oscar Purner
• December 14 – John Anderson

• February 26 – Cy Bentley, 22, pitcher and right fielder for the 1872 Middletown Mansfields.

• 1873 season at Baseball-Reference.com
• Charlton's Baseball Chronology at BaseballLibrary.com
• Retrosheet.org

• Levine, Peter (1985). A.G. Spalding and the Rise of Baseball: The Promise of American Sport. New York: Oxford University Press. ISBN 0-19-503552-6