Frederick Raymond "Fritz" Ostermueller (September 15, 1907 – December 17, 1957) was an American left-handed pitcher in Major League Baseball from 1934 to 1948, playing for the Boston Red Sox, St. Louis Browns, Brooklyn Dodgers, and Pittsburgh Pirates.

"[2] Ostermueller began his career in his home town of Quincy, Illinois, before finishing high school.

In 1929 he had 95 strikeouts for the Shawnee Robins of the Western Association, and later played for the Rochester Red Wings.

Ostermueller made his major league debut on April 21, 1934 with the Boston Red Sox, pitching seven seasons for them, chiefly as a starter.

[4] Ostermueller coached in college and built and became the owner-operator of the Diamond Motel in Quincy, Illinois.