Sizing John will miss his intended seasonal reappearance in the Fortria Chase at Navan this weekend having had a small wind procedure on Monday.
The 2017 Cheltenham Gold Cup winner has not been seen since finishing well beaten in the Leopardstown Christmas Chase and was unable to defend his crown in March due to a fractured pelvis.
His latest setback is not serious, but trainer Jessica Harrington will now need to reassess his programme and is eyeing a Christmas comeback.
She told her www.unibet.co.uk blog: “Sadly Sizing John will not make his intended seasonal reappearance in Navan this weekend after we discovered a small problem with his wind.
“He did a routine piece of work yesterday (Sunday) morning and we weren’t 100 per cent happy with him so the vets checked him out this morning and we found out he needed to undergo a small wind procedure, which was conducted this afternoon and all went well.
“It’s not serious, but he will be on the easy list for two to three weeks before resuming full work and, all being well, we hope to have him ready in time for Christmas.”