UFC women’s flyweight champion Valentina Shevchenko will not be defending her belt at UFC 251.

Her flyweight title defense against Joanne Calderwood, slated for June 6 in Perth, Australia, is on hold because of an undisclosed injury, according to a person with knowledge of the situation who requested anonymity since the UFC has yet to make an announcement. The fight is expected to be rescheduled, although a date to rebook hasn’t been set.

Calderwood first revealed the development Tuesday in an interview with MMA Fighting.

“We got word last week that it’s going to get pushed back,” Calderwood said of the fight. “Not because of this whole (coronavirus pandemic), but something on her end. I’m not sure if I’m supposed to say that, but we know for sure that it’s not going to be on June 6. I don’t know, I’m not sure what happened or what’s what, but it’s been pushed back. It could be a blessing in disguise.”

Calderwood subsequently said during an Instagram Live session that she hoped for the fight to be rebooked in either July or August.

Shevchenko (19-3 MMA, 8-2 UFC) has defended her title three consecutive times since winning the inaugural belt by outpointing former strawweight champion Joanna Jedrzejczyk in December 2018 at UFC 231.

Shevchenko last fought in February, stopping Katlyn Chookagian at UFC 247. The champion remains undefeated at 125 pounds, with her only two losses in the UFC coming at bantamweight to current dual champion Amanda Nunes.

Meanwhile, Calderwood (14-4 MMA, 6-4 UFC) has compiled a record of 3-1 since moving back up to 125 pounds. Calderwood most recently defeated Andrea Lee via split decision last September at UFC 242.