Gurgel, who was scheduled to face Carina Damm in a non-title fight, tweeted Thursday that she will need to undergo surgery.
"I just took an MRI of my knee yesterday and results came back," Gurgel said. "I completely tore my ACL."
Despite having to be sidelined for the near future, the 27-year-old Gurgel was in positive spirits.
"Regardless of my current situation, I'm happy cause I have an amazing life, the best hubby, a great family and great people that surround me."
Gurgel (11-1) won the Bellator's 115-pound tournament last year to become the promotion's first women's champion. She fought once this year, beating Karina Hallinan in a non-title bout in March via unanimous decision.
This past February, Gurgel tied the knot with UFC and Strikeforce veteran Jorge Gurgel.