Popov was involved in a serious car accident on November 17, 2015, while returning from training near Sölden. He was one of two passengers in a vehicle driven by Drago Grubelnik, then head coach of the Bulgarian ski team, who was also accompanied by his assistant Mitko Hristov. All three occupants of the car were injured in the crash, with Grubelnik later dying of his wounds in a hospital in Murnau, Germany. Popov eventually returned to the FIS circuit for the 2016–17 season, and featured at the 2017 World Championships, where he finished 27th overall in slalom and 30th overall in the giant slalom event.