39. Ed Reulbach

When Ed Reulbach arrived in 1905, he transitioned instantly from a standout college athlete into one of the most difficult pitchers to hit in the National League. He matured into a mainstay of the Cubs’ rotation just as the team began its historic run toward back-to-back championships in 1907 and 1908. His success was staggering; he led the National League in winning percentage for three consecutive years (1906–1908), a feat of consistency matched only by the legendary Lefty Grove. He arrived with a "shadowing" windup that hid the ball from hitters and quickly became a force who could suppress runs as well as any pitcher in the Deadball Era.

The absolute pinnacle of his career arrived during the white-hot pennant race of 1908. On a single afternoon in late September, Reulbach authored a feat that remains the only one of its kind in Major League history: he pitched and won both ends of a doubleheader against the Brooklyn Superbas, throwing two complete-game shutouts in the same day. He was a master of run prevention, finishing with an ERA under 2.00 in four of his first five seasons. This period of dominance saw him surrender fewer than 6 hits per 9 innings in 1906, a ratio of efficiency that would stand as a benchmark for over 60 years.

His identity was synonymous with the Cubs' championship pedigree. A two-time World Series winner, Reulbach was a big-game specialist who famously threw a one-hitter in the 1906 Fall Classic. He was a workhorse who rarely showed signs of fatigue, using his towering 6'1" frame and a high leg kick to overwhelm hitters. He concluded his primary stay in Chicago with 136 wins and a microscopic 2.24 ERA, leaving behind a legacy as one of the most effective and durable arms to ever call the West Side Grounds home.

The chapter eventually closed in 1913, when he moved to Brooklyn, followed by a later star turn in the Federal League. He left the organization as a statistical titan and the last surviving member of the 1907–1908 championship squads. He proved that to rule the mound, you needed more than just a live arm—you needed the intellect to outthink the hitter and the stamina to outlast the sun.

In a long-overdue tribute to his massive impact, the organization named him as an inaugural member of the Chicago Cubs Hall of Fame in 2021.