Aidan O'Brien admitted the Qipco 1000 Guineas at Newmarket is likely to come too soon for ante-post favourite Clemmie.
The daughter of Galileo was as short as 3-1 for the first fillies' Classic of the campaign after winning three of her five starts as a juvenile, completing her hat-trick in the Cheveley Park Stakes at Newmarket in September.
However, O'Brien revealed his charge suffered a minor setback recently and she appears to be losing the race to line up on the Rowley Mile on May 6.
O'Brien told At The Races: "Because of the little hold-up she had, we had to go easy for a week or 10 days and we would have to force her to get her to Newmarket.
"She's in full work at the moment, but it's probably going to come a bit too quick for her."
The Ballydoyle handler could still play a formidable hand in the 1000 Guineas, with Happily, September, I Can Fly and Magical all in contention.
Gustav Klimt usurped stablemate Saxon Warrior as favourite for the 2000 Guineas with some bookmakers following an impressive comeback success at Leopardstown on Saturday.
Aidan O'Brien on unbeaten 2000 Guineas hope Saxon Warrior: "He's got a couple of weeks to go and he's progressing along lovely. So far so good." pic.twitter.com/PGoX17cFDj— At The Races (@AtTheRaces) April 16, 2018
O'Brien confirmed both horses are set to run at Newmarket early next month.
He said: "That is what we're looking at at the moment.
"We have another couple of weeks to go, but he (Saxon Warrior) is progressing along lovely.
"We never thought he was short of pace."
Even by his remarkable standards the first weekend in May could be huge for O'Brien, with Mendelssohn firmly on target to run in the Kentucky Derby on May 5th.
There has been plenty of discussion about whether Ryan Moore will ride at Newmarket or in America, but O'Brien is in no rush to finalise plans.
"I try to take one day at a time. Hopefully we'll have runners in the two Guineas and hopefully Mendelssohn will go to America," the trainer added.
"We'll usually decide those things a week before, or when their serious work is over."
"Mendelssohn is in good form," Aidan O'Brien tells us on Racing News.
"He came back well from Dubai and in the next couple of weeks we'll step up his work. Everyone seems happy with him at the moment." pic.twitter.com/C8hPhzVN3Z— At The Races (@AtTheRaces) April 16, 2018
Mendelssohn earned his trip to Churchill Downs with a jaw-dropping performance in the UAE Derby at Meydan last month and O'Brien is delighted with how he has recovered from his Dubai exertions.
He said: "He's in good form. Obviously he's had an easy couple of weeks and he came back well.
- Digital Desk and Press Association