An injury has forced UFC flyweight champion Demetrious Johnson out of his scheduled title defense on April 13, according to a report by Ariel Helwani on Tuesday's UFC Tonight.

Johnson was expected to fight John Moraga on the date, at The Ultimate Fighter 17 Finale in Las Vegas.

It would have been a quick turnaround for Johnson, who went five rounds in a unanimous decision win over John Dodson at UFC on FOX 6 on Jan. 26. That win marked his first successful title defense after capturing the belt last September.

He had hoped to gun for his second defense against Moraga, a 28-year-old Arizona-based fighter who is 13-1 and riding a seven-fight win streak. Moraga has two consecutive finish wins in his UFC run, with a submission over Chris Cariaso and a knockout of Ulysses Gomez.

A hunt is on for a replacement for the scuttled main event.

Other matches scheduled for the show include a women's match between Miesha Tate and Cat Zingano, and a heavyweight fight pitting Gabriel Gonzaga vs. Travis Browne.