The 28-year-old spent Sunday night in hospital after his BMW hit two parked vehicles and flipped onto its roof, although he was discharged on Monday afternoon after being cleared of serious injury. The incident came 24 hours after Seymour had been abused by fans for his part in Hull's surprise 36-16 defeat at Widnes.
Now Seymour's wife Roseanne has revealed her husband was "desperate" and claimed he was suffering from depression, suggesting he may have tried to take his own life.
She told a Facebook group created to wish her husband a speedy recovery: "I'm suffering from severe shock that my husband was so desperate and could attempt such a horrific thing.
"He is getting the help he needs and your support has helped greatly. Depression is a silent killer - I want each and every one of you to know that we feel so grateful to you."
Seymour, who is in his second season in Super League, has been placed on leave by his club and the couple are believed to have left the city to go on a break and begin the process of trying to get his life back in order.
Neither Hull nor the Rugby Football League were prepared to make any official comment but it is understood Seymour has received counselling from representatives of both organisations, and the Super League players' association, 1eague3, has promised its help.
Ernie Benbow, who is chief executive of 1eague3 as well as a co-founder of State of Mind which was established two years ago following the death of former Great Britain hooker Terry Newton, says Seymour's team-mates may also need assistance.
"We've only just been informed of the news but we would certainly want to offer whatever help we can," he said. "It may have affected the group as a whole because the news will have come as a shock."
Former Hull forward Hame Lauaki, now at Wigan, sent a goodwill message to the player, tweeting: "Hope everyone gathers to support Brett Seymour through this difficult time.. Get well soon bra... Sad to read what he gone thru."
- Sports & Recreation