Club staff rushed to Hull Royal Infirmary on Monday morning after being told the player had been involved in a car crash. It is not thought Seymour's injuries are life-threatening.
"The only information we have is that he has been involved in a traffic accident and he's in hospital," said media manager Matt Holden.
Seymour, 28, who joined the club from New Zealand Warriors at the start of last season, played in Hull's 36-16 defeat at Widnes on Saturday.
- Sports & Recreation
- Hull Royal Infirmary