WWE issued the following on Saturday afternoon.
“NXT Champion Finn Bálor suffered an ankle injury on Saturday during an NXT Live Event in Nashville, Tenn. According to WWE physician Dr. Chris Amann, ‘Finn Bálor suffered an ankle injury, and will be unable to compete tonight.’ The NXT Champion will undergo further evalution on Monday, Amann said.”
WWE: Finn Bálor injures ankle during NXT Live Event in Nashville, Tennessee