Dermot Weld will run only one of his two remaining entries in the Tattersalls Irish 2,000 Guineas at the Curragh on Saturday, with Mustajeeb more likely than Alkasser at this stage.
Both colts are owned by Hamdan Al Maktoum, but Mustajeeb has arguably achieved more, having beaten a solid yardstick in the older Brendan Brackan in the Amethyst Stakes at Leopardstown.
"Both horses are working well, but only one of them will run," said the in-form Weld.
"At the moment we are leaning towards Mustajeeb and Pat Smullen will partner whichever one we eventually side with."
Aidan O'Brien has five possibles but there is no denying which is his number one hope, despite his disappointing effort in the English equivalent.
"War Command is our horse in Saturday's race," said the Ballydoyle-based trainer.
"We will also run Fountain Of Youth, Michaelmas and Great White Eagle, while Johann Strauss is also under consideration.
"All five are working very well."
Richard Hannon expects the stiff nature of the Curragh to bring out the best in Shifting Power, who was supplemented.
The colt defied his 50-1 price in the market to finish fourth, beaten only three lengths by stablemate Night Of Thunder in the first Classic of the season at Newmarket.
While Night Of Thunder heads for the St James's Palace at Royal Ascot, Shifting Power will meet Guineas second Kingman again on Saturday.
But Hannon hopes more emphasis on stamina in Ireland can help his Free Handicap winner repay connections' faith.
"He ran very well in the English Guineas to finish fourth and was running on," Hannon told At The Races.
"I think the track will suit him at the Curragh. It doesn't suit us too much that Kingman's going, but there you go.
"He has to go, we can go up to a mile and a quarter later on but I think he's well worth his chance and if he finishes in the (first) three, we get our money back. I think the track will really suit him.
"Our Guineas is always the best race, the champion two-year-old ran and just because our horse won at 40-1 people think something went wrong.
"Our horse (Night Of Thunder) started over on the far side with Kingman and ended up on the near side. I'm not saying he's going to go through the season unbeaten, but I don't think there was much fluke about it."
Shifting Power's addition to the Classic means there are 16 possibles for the race.
As expected, John Gosden's Kingman remains in the mix but he is the only other challenger from Britain.
Ger Lyons has left in Obliterator but warned on Monday he was an unlikely runner unless there was good in the going.
Prince Of All, Mandatario and Big Time are others to note.