Yorkshire’s season opener did not unfold the way his team had hoped, and his trainers accept that the setback may leave him vulnerable heading into the Festival Stakes at Rosehill.

The gelding finished at the tail of the field first-up in The Hunter (1300m), later found to be suffering from cardiac arrhythmia.

He had arrived at the race as favourite after winning six of his previous eight outings, and while co-trainer John O’Shea felt the market had overreached, he expected a far stronger showing.

“There was a lot of market support for him, but it wasn’t stable inspired,” O’Shea said.

“We were adamant the horse needed a run or two, although he was never going to run that badly because he had trialled up really well and was going well at home.

“He definitely had cardiac arrhythmia, but it has rectified and his KPI’s post-that have been excellent.”

Yorkshire still needs to clear a few final checks before he returns in the Festival Stakes (1500m), though signs to date indicate he has bounced back well.

O’Shea noted that cardiac arrhythmia is not unusual in racehorses and that a behind-the-barriers resaddling at Newcastle may also have unsettled him.

His recent work has convinced the stable he is trending the right way, and they view Saturday’s run as an ideal lead-in to The Ingham (1600m) at Randwick.

“There is no doubt he has got improvement from Saturday,” he said.

“Saturday is about getting back into the game with a positive run and then allowing us the opportunity to bounce off that into The Ingham.”

Despite caution from the stable, Yorkshire remained a $3.20 favourite on Friday, ahead of Accredited ($8) and Arctic Glamour ($9.50).

If you’re punting on the Festival Stakes, compare the latest odds through the top Australian betting sites.