Theodore P. Breitenstein was an American Major League Baseball pitcher from St. Louis, Missouri who played from 1891 to 1901 for the St. Louis Browns/Cardinals and the Cincinnati Reds. He is best known for throwing a no-hitter in his first Major League start, along with the "Pretzel Battery" with fellow German-American battery mate Heinie Peitz.

The following are the baseball events of the year 1891 throughout the world.