The Colorado Rockies had a rough run during the 2025 MLB season. At the 50-game mark, they made history with the worst start in the modern MLB era. By September, they finished the season with the worst MLB record of the year: 43-119. At Coors Field, they finished 25-56, which marked the most home losses in franchise history. They also finished the season with the worst run differential in modern MLB history, at minus-424.

The Chicago White Sox struggled at an even worse historical level during the 2024 season. At the end of September, the White Sox broke the modern MLB era record for most losses in a season.

Check out the historical rundown below:

Worst Records, MLB History br/> (Min. 150 Games Played; W-L, Win Pct)

1899 Cleveland Spiders: 20-134, .130

1916 Philadelphia A's:

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