Wayne Lordan was taken to hospital after being stood down for the day after suffering a heavy fall during the Dubai Duty Free Irish Derby on Sunday.
The jockey's mount San Antonio suffered a fatal injury during the 1m4f contest at the Curragh, with Lordan being tossed off and hitting the ground hard.
He was due to have three more rides on the day, but was stood down following the fall.
READ MORE: Irish Derby full result as Aidan O'Brien wins his 100th European Classic
Aidan O'Brien confirmed shortly after the race that the jockey was "okay".
Auguste Rodin gave O’Brien his 100th European Classic win as he fended off stablemate Adelaide River in the race.
The Epsom hero was also a first winner in the race for Ryan Moore as he came home a length and a half clear, with Covent Garden ensuring a clean sweep of the places for the Ballydoyle team in third.
Adelaide River set the pace under Seamie Heffernan with Moore happy to take a lead into the straight.
When he loomed upsides two furlongs from home it looked as if Auguste Rodin would go away and win impressively, but it was not until the final 100 yards that he eventually put the race to bed.
Auguste Rodin is the first horse since Harzand in 2016 to follow up victory at Epsom in the Irish equivalent.
Speaking after the race, winning jockey Moore said: “It’s a hard one, because poor Wayne there – I just hope he’s OK.
“It didn’t suit this horse because it was a messy race. I ended up getting to the front early after us not going quick. He was just waiting when he was in front then.
“He’s a lovely horse and I’m very lucky too. I’m grateful to win this race, it’s just a shame the way it turned out there.
“He’s a lovely horse and that’s what it’s about really, it’s about the horses. He’s a beautiful horse.”
Lordan was taken to Tallaght Hospital for tests, while O’Brien confirmed Dee Stakes winner San Antonio had sustained a fatal injury.
He told Racing TV: “It’s terrible for San Antonio. When things go wrong in any sport after going 75 per cent of the way and the pressure is really going on, that’s when devastating stuff can happen and it does happen.
“Thank god Wayne is OK, but it’s terrible for San Antonio and we’re so sorry for everyone – that lads that looked after him and rode him and did everything with him.”
Get the latest sports headlines straight to your inbox by signing up for free email alerts
