Borg's manager, Ali Abdelaziz, told ESPN that Borg had a "family emergency."
Borg was absent from the card's virtual media day Thursday and his withdrawal was announced after it. New signee Gustavo Lopez will fill in and fight Dvalishvili, UFC officials told ESPN. The new bout will be contested at a 140-pound catchweight.
Borg tweeted a photo of his son, Anthony, on Thursday afternoon with the text: "Family first, see you soon son." He did not go into any further detail. Anthony Borg was born in 2018 with the brain condition hydrocephalus. He has had several surgeries to treat the issue.
Ray Borg, 26, had been scheduled to fight after just a month turnaround, attempting to bounce back from a unanimous decision loss to Ricky Simon on May 13. The New Mexico native was on a two-fight winning streak before that bout.
Dvalishvili (10-4) has won three straight. The 29-year-old, who was born in the Republic of Georgia and lives and trains in New York, is coming off a unanimous decision win over Casey Kenney in February.
Lopez (10-4), a 30-year-old Las Vegas resident, was on a three-fight winning streak in the Combate Americas promotion and is its current bantamweight champion.
The promotion cleared Lopez to fight in the UFC on Saturday after CEO Campbell McLaren initially tweeted Thursday that Lopez is still under contract with Combate and him fighting this weekend for the UFC would be a "bad move."
After Lopez's manager, Daniel Rubenstein, tweeted that he had "officially requested" Lopez's release, McLaren said in a statement that Combate had "decided to allow Gustavo Lopez to move forward and fight in the UFC this Saturday night. We wish him the best of luck with the rest of his career."