1940s baseball seasons
129 team seasons across 10 years.
1949
- Boston Red Sox — 35 players
- Chicago Cubs — 40 players
- Chicago White Sox — 44 players
- Cincinnati Reds — 35 players
- Cleveland Indians — 32 players
- Detroit Tigers — 31 players
- New York Yankees — 37 players
- Philadelphia Athletics — 28 players
- Philadelphia Phillies — 33 players
- Pittsburgh Pirates — 37 players
- St. Louis Browns — 37 players
- St. Louis Cardinals — 37 players
- Washington Senators — 37 players
1948
- Boston Red Sox — 34 players
- Chicago Cubs — 37 players
- Chicago White Sox — 34 players
- Cincinnati Reds — 36 players
- Cleveland Indians — 36 players
- Detroit Tigers — 33 players
- New York Yankees — 35 players
- Philadelphia Athletics — 31 players
- Philadelphia Phillies — 38 players
- Pittsburgh Pirates — 33 players
- St. Louis Browns — 37 players
- St. Louis Cardinals — 37 players
- Washington Senators — 35 players
1947
- Boston Red Sox — 41 players
- Chicago Cubs — 36 players
- Chicago White Sox — 31 players
- Cincinnati Reds — 38 players
- Cleveland Indians — 38 players
- Detroit Tigers — 29 players
- New York Yankees — 39 players
- Philadelphia Athletics — 31 players
- Philadelphia Phillies — 41 players
- Pittsburgh Pirates — 42 players
- St. Louis Browns — 31 players
- St. Louis Cardinals — 30 players
- Washington Senators — 36 players
1946
- Boston Red Sox — 39 players
- Chicago Cubs — 46 players
- Chicago White Sox — 39 players
- Cincinnati Reds — 35 players
- Cleveland Indians — 47 players
- Detroit Tigers — 37 players
- New York Yankees — 46 players
- Philadelphia Athletics — 41 players
- Philadelphia Phillies — 49 players
- Pittsburgh Pirates — 43 players
- St. Louis Browns — 44 players
- St. Louis Cardinals — 37 players
- Washington Senators — 36 players
1945
- Boston Red Sox — 37 players
- Chicago Cubs — 36 players
- Chicago White Sox — 27 players
- Cincinnati Reds — 34 players
- Cleveland Indians — 36 players
- Detroit Tigers — 37 players
- New York Yankees — 32 players
- Philadelphia Athletics — 37 players
- Philadelphia Phillies — 47 players
- Pittsburgh Pirates — 32 players
- St. Louis Browns — 31 players
- St. Louis Cardinals — 37 players
- Washington Senators — 34 players
1944
- Boston Red Sox — 33 players
- Chicago Cubs — 40 players
- Chicago White Sox — 29 players
- Cincinnati Reds — 39 players
- Cleveland Indians — 35 players
- Detroit Tigers — 32 players
- New York Yankees — 32 players
- Philadelphia Athletics — 35 players
- Philadelphia Phillies — 40 players
- Pittsburgh Pirates — 33 players
- St. Louis Browns — 33 players
- St. Louis Cardinals — 27 players
- Washington Senators — 37 players
1943
- Boston Red Sox — 31 players
- Chicago Cubs — 40 players
- Chicago White Sox — 29 players
- Cincinnati Reds — 30 players
- Cleveland Indians — 34 players
- Detroit Tigers — 27 players
- New York Yankees — 26 players
- Philadelphia Athletics — 44 players
- Philadelphia Phillies — 42 players
- Pittsburgh Pirates — 32 players
- St. Louis Browns — 37 players
- St. Louis Cardinals — 28 players
- Washington Senators — 38 players
1942
- Boston Red Sox — 26 players
- Chicago Cubs — 39 players
- Chicago White Sox — 33 players
- Cincinnati Reds — 35 players
- Cleveland Indians — 36 players
- Detroit Tigers — 31 players
- New York Yankees — 31 players
- Philadelphia Athletics — 38 players
- Pittsburgh Pirates — 35 players
- St. Louis Browns — 35 players
- St. Louis Cardinals — 33 players
- Washington Senators — 36 players
1941
- Boston Red Sox — 31 players
- Chicago Cubs — 41 players
- Chicago White Sox — 32 players
- Cincinnati Reds — 35 players
- Cleveland Indians — 41 players
- Detroit Tigers — 37 players
- New York Yankees — 27 players
- Philadelphia Athletics — 40 players
- Philadelphia Phillies — 34 players
- Pittsburgh Pirates — 38 players
- St. Louis Browns — 35 players
- St. Louis Cardinals — 38 players
- Washington Senators — 36 players
1940
- Boston Red Sox — 33 players
- Chicago Cubs — 29 players
- Chicago White Sox — 27 players
- Cincinnati Reds — 33 players
- Cleveland Indians — 30 players
- Detroit Tigers — 35 players
- New York Yankees — 27 players
- Philadelphia Athletics — 34 players
- Philadelphia Phillies — 42 players
- Pittsburgh Pirates — 36 players
- St. Louis Browns — 32 players
- St. Louis Cardinals — 38 players
- Washington Senators — 35 players