TOKYO (AP) — A 75-year-old Japanese equestrian rider will not be able to become the oldest competing Olympian of all time in Rio de Janeiro because of an illness to his horse.

Hiroshi Hoketsu was unable to meet the criteria to join the qualifying trials for the Japanese team, Kyodo news agency reported.

"I don't want to push the horse, so unfortunately I have given up upon the dream of competing in the Rio Olympics," Hoketsu said. "There's nothing decided about the future. First I'd like to prioritize getting the horse well again."

Hoketsu, who made his Olympic debut in Tokyo in 1964 and at 71 was the oldest athlete to compete at the 2012 London Games, has been training in the Netherlands and Germany but hadn't been able to take part in competitions after his horse fell ill.

Hoketsu would have become the oldest athlete to compete at the Olympics had he qualified for Rio, overtaking Swedish shooter Oscar Swahn, who participated in the 1920 Antwerp Games at the age of 72.

Hoketsu was aiming for his fourth Olympics after also appearing at the 2008 Beijing Games, where he finished ninth in team dressage and 35th in individual dressage.

In 2012, Hoketsu competed in individual dressage, finishing 40th.

Hoketsu also qualified for the 1988 Seoul Olympics, but was unable to compete when his horse was quarantined.