The world-class champion kickboxer is injured and out of his co-main event fight with Jake Heun at World Series of Fighting 26 on Dec. 18 in Las Vegas, WSOF president Ray Sefo confirmed with MMA Fighting's Ariel Helwani. Sherdog was the first to report the news.
In Spong's place will be Clinton Williams, according to Sefo. Williams (7-2), a well-muscled heavyweight, will be making his WSOF debut. The 31-year-old has won four of his last five fights. Williams is coming off a third-round submission of Jared Hatch last month at SteelFist Fight Night 38.