Flemenstar is set to have the Queen Mother Champion Chase as his Cheltenham Festival target following his reverse in the Lexus Chase at Leopardstown.
After putting previously unbeaten chaser Sir Des Champs to the sword with a brilliant display in the two-and-a-half-mile John Durkan Memorial Punchestown Chase, Flemenstar had to settle for third in the Grade One event.
Having travelled and jumped with his trademark panache under Andrew Lynch, the seven-year-old looked poised to go on and record an impressive victory rounding the home turn, but the complexion of the race quickly changed.
Flemenstar appeared a weary horse after jumping the final fence and although he stuck to his task well enough to finish third, beaten just three-quarters of a length by Tidal Bay in a barnstorming finish, Casey feels his stable star's stamina limitations were exposed.
The trainer does not feel it would be right to test his charge over an extended three and a quarter miles at Cheltenham in March and with the two-mile-five-furlong Ryanair Chase seemingly of no appeal, he is set to tackle the formidable Sprinter Sacre over the minimum trip instead.
Asked about whether the Gold Cup was still being considered, Casey said: "We'll have to rule that out. He won't get that extra two furlongs.
"You'd think he was going to win coming to the last fence (in the Lexus), he was cruising. He just found nothing after the last 100 yards.
"The Queen Mother, that will be it. The two-mile Champion Chase.
"That will be the one we'd go for.
Casey is confident that Flemenstar is capable of shaking up the current Champion Chase favourite Sprinter Sacre.
"Our lad is a great jumper and has plenty of speed. He jumped well (on Friday) but every time he landed he was wanting to get going," said the trainer.
"In Cheltenham, if we went for the Queen Mother, he'd have to go there, Andrew would be letting him stride on and we'd give that other lad (Sprinter Sacre) something to think about then!
"We'll have to rule that out. He won't get that extra two furlongs" - Peter Casey says no to a Gold Cup tilt
"That's what we're going to try and do anyway."
Casey will consult Flemenstar's owner before deciding on a next port of call, but is leaning away from another crack at three miles in the Hennessy Gold Cup back at Leopardstown in February.
Casey said: "We'll have to think about where we go next and talk to the owner.
"I don't think we'll go for the Hennessy. There is the Red Mills Chase at Gowran in the middle of February. Whether we'll go down there or not I don't know."