Pearl Gonzalez and Brogan Sanchez are being asked to step up.

Previously announced as the co-headliners for Invicta FC 37, the two flyweights now meet in the Oct. 4 main event at Memorial Hall in Kansas City, Kan.

Officials on Monday announced atomweight champion Jinh Yu Frey has been forced to withdraw from the originally scheduled main event opposite Ashley Cummins.

Per a press release from the promotion, Frey’s withdrawal is due to an injury. This was to be her second defense of the 105-pound title after winning a split decision in a rematch against Minna Grusander at Invicta FC 33 last December.

Since moving to Invicta from the UFC, Gonzalez has gone 3-1, most recently dropping a technical decision to Vanessa Porto in a bout for a vacant 125-pound championship. Walker is 6-0 as a pro, 2-0 in Invicta, with both of those wins coming by way of split decision.

Invicta FC 37 airs live on UFC Fight Pass. See the updated card below:

Pearl Gonzalez vs. Brogan Sanchez

Mariya Agapova vs. Marilia Santos

Kay Hansen vs. Nicolle Caliari

Shino VanHoose vs. Lindsey VanZandt

Linda Mihalec vs. Marisa Messer-Belenchia

Megan Cawley vs. Hope Chase

Jordan Kaaze vs. Claire Johnson