Ostovich, 27, suffered a fractured orbital bone during an alleged attack by her husband, professional MMA fighter Arnold Berdon, earlier this month in Hawaii. Afterward, her management announced she would not fight on Jan. 19 due to injury.
Ostovich's manager, Brian Butler-Au, told ESPN on Tuesday that Ostovich sought a second opinion on her injuries this week and has been cleared to remain in the fight.
"She never really wanted to be off of this fight," Butler-Au said. "When everything happened, it was very emotional. The injuries were significant enough that, combined with the emotions of everything that was going down, we made a decision to pull out of the fight.
"Now that things are settling out and the swelling of the injury is going down, Rachael got a second opinion and everything will work out to where she can keep this fight."
UFC president Dana White also confirmed to ESPN that the 125-pound fight is back on.
VanZant celebrated the news in a Twitter post and voiced support for Ostovich.
FIGHT STILL ON!!!!! I couldn't be more great full to @rachaelostovich Yes we are going to war with each other in the cage, but I stand by her side with her ongoing battle at home. Let's put on a fight and show these people how strong we are. #GirlPower #UFC pic.twitter.com/DDfNDV65jt— Paige VanZant (@paigevanzant) November 27, 2018
The Honolulu Police Department took Berdon into custody last week. He has been charged with second-degree assault, and his next court hearing is scheduled for Dec. 18. Ostovich also has been granted a restraining order against Berdon.
Ostovich (4-4) is 1-1 in the UFC. VanZant (7-4) will be coming off a one-year injury layoff.
The UFC Fight Night event will take place at Barclays Center in Brooklyn and air on ESPN+. It will mark the first event of a five-year partnership between the UFC and ESPN.