UFC officials did not elaborate on the reason for Hall’s withdrawal.
UFC St. Louis takes place Jan. 14 at the Scottrade Center in St. Louis, Missouri. A featherweight bout between veteran contender Jeremy Stephens and up-and-comer Doo Ho Choi is slated to headline the event.
Belfort, 40, said prior to the event that he planned to retire after his fight with Hall unless he was paid $10 million to compete again, bringing an end to his 21-year career.
As of this writing, it is unclear if the UFC will re-book Belfort vs. Hall.