The UFC did not report what forced Brunson out of the fight.
Mousasi has won three of his past four bouts. The former Strikeforce champion is looking to build off February’s unanimous decision victory over Thales Leites.
Santos has rattled off four straight wins. The Brazilian is fresh off last month’s knockout over Nate Marquardt.
T-Mobile Arena in Las Vegas, Nevada hosts the historic card.
Here is the show’s updated lineup:
Preliminary Card:
(UFC Fight Pass 6:45PM ET/3:45PM PT)
Takanori Gomi vs. Jim Miller
Joe Lauzon vs.