The light heavyweight bout, a title eliminator offering the chance to meet Strikeforce champion Dan Henderson, was set for the undercard of the promotion's first event under Zuffa ownership after the sale was completed on March 11.
"We'll probably have an opponent [for Mousasi] in the next day or two," Coker said.
Kyle (18-8-1) has not fought since suffering a broken hand in a heavyweight fight against Antonio Silva in early December. The 31-year-old, competing out of the American Kickboxing Academy in San Jose, Calif., had undergone something of a career resurgence prior to being stopped by Silva on short notice.
Against Mousasi (30-3-1), who failed to successfully defend his Strikeforce light heavyweight belt in his first attempt against Muhammed Lawal one year ago, Kyle was set to face his toughest opponent at 205 pounds since he upended Rafael Cavalcante by knockout in 2009.
Josh Gross covers mixed martial arts for ESPN.com.