Retired jockey Pat Smullen has ruled out riding in his charity race at the Irish Champions Weekend after a setback in his health.

The multiple Group One-winning jockey announced his retirement in May, having undergone treatment for pancreatic cancer after being diagnosed in March last year.

Smullen had been planning to return to the saddle for the Pat Smullen Champions Race For Cancer Trials at the Curragh on September 15, but has had to withdraw on medical advice.

The race is part of fund raising activities over the two-day meeting in aid of cancer research, with Smullen keen to promote awareness of pancreatic cancer.,

"Unfortunately I've had a setback with my health and have to undergo chemotherapy," Smullen said.

"On advice from my medical team, I am unable to ride in the Champions Race for Cancer Trials Ireland.

"I am bitterly disappointed not to be able to take part in this very special race - I was really looking forward to riding against such a brilliant group of champions, especially at the Curragh.

"I've spoken to Horse Racing Ireland, who are helping me with the fundraising activity over Irish Champions Weekend, and I am more determined than ever that the fundraising activity goes ahead because pancreatic cancer needs more awareness now than ever before."

Smullen was the stable rider for Dermot Weld and rode Vinnie Roe in three Melbourne Cups with his best result second in 2004 behind Makybe Diva.

While Smullen will not be able to take part, nine champions - Sir Tony McCoy, Ruby Walsh, Charlie Swan, Johnny Murtagh, Richard Hughes, Paul Carberry, Joseph O'Brien, Kieren Fallon and Ted Durcan - are all due to be in action.