Capcom confirmed that the executive's physical condition "heavily deteriorated" while on the Asian leg of a promotional tour for the game, EventHubs reports.
"I would like to bring something else to everyone's attention," the publisher announced. "Shortly after the Street Fighter X Tekken promotion in Asia, Ono-san's physical condition rapidly and heavily deteriorated and he had to be taken to the hospital.
"Because of his hospital tenure he will not be performing work-related affairs for a while. Ono's well-being is very important to us, and we wish for his steady recovery."
Ono's first notable Capcom project was Dino Crisis 2 in 2000, on which he served as publicist. He went on to work on the Resident Evil series and serve as producer on Street Fighter IV.
He was travelling the world to market Street Fighter X Tekken with his Namco counterpart Katsuhiro Harada. His current condition is not known.
Watch a trailer for Street Fighter X Tekken below: