Jacob Ellsworth Daubert (April 7, 1884 – October 9, 1924) was an American first baseman in Major League Baseball who played for the Brooklyn Superbas[a] and Cincinnati Reds.

[1] Baseball historian William C. Kashatus observed that Daubert was "a steady .300 hitter for 10 years of the Deadball Era" who "never fielded below the .989 mark.

In 1895, at the age of eleven, the young Daubert joined his father and two brothers at work in the local coal mines.

[3] In 1906, Daubert left his job at the mines and signed a contract with a baseball team in Lykens, Pennsylvania.

After playing the first part of the season with Toledo of the American Association, Daubert went back to Tennessee and joined the Memphis club.

On August 15, 1914, Daubert tied Cy Seymour's MLB record with four sacrifice bunts in one game.

When the season was cut short due to World War I and the Spanish flu epidemic, major league owners prorated player salaries.

[3] After the dispute started, Brooklyn owner Charles Ebbets traded him to Cincinnati for outfielder Tommy Griffith.

Daubert was a trailblazer in baseball's unionization movement, a controversial role that may have been a factor in his omission from the Hall of Fame.

[10] A salary dispute with Charles Ebbets, owner of the Dodgers, was a major factor in Daubert's transfer to Cincinnati in 1919.

[3] Daubert left the Reds late in the 1924 season after falling ill during a road trip to New York.

[11] He died in Cincinnati one week after the operation, with the doctor citing "exhaustion, resulting in indigestion, [as] the immediate cause of death".

[11] It was later discovered that Daubert suffered from a hereditary blood disorder called hemolytic spherocytosis, which contributed to his death.

At the time of his death, he ranked among the major league career leaders in games (4th, 2,001), putouts (4th, 19,634), assists (5th, 1,128), total chances (4th, 20,943) and double plays (3rd, 1,199) at first base; he was also among the NL's leaders in hits (7th, 2,326), triples (9th, 165), at bats (9th, 7,673), games played (10th, 2,014) and total bases (10th, 3,074).