Aidan O'Brien has nominated Puerto Rico as his primary contender for the Betfred 2000 Guineas, with the Ballydoyle mastermind in no rush to commit Albert Einstein to the Newmarket classic following his Newbury defeat.

Once the winter favourite for the Rowley Mile showpiece, Albert Einstein has endured a turbulent spring. A disappointing return in the Curragh's Gladness Stakes dented his towering reputation, before a computer error saw him accidentally scratched from the Guineas entirely.

Seeking to salvage his Newmarket ticket, O'Brien sent the highly regarded colt to Saturday's Greenham Stakes. While he showed marked improvement, he ultimately had to settle for third behind Karl Burke’s Alparslan and Eve Johnson Houghton’s Zavateri.

Speaking on Racing TV’s Luck on Sunday, O'Brien offered a candid assessment of the colt's performance and the tactical decisions that may have hindered his chances. He noted jockey Ryan Moore anticipated a strong gallop, but when the early pace proved sluggish, the colt travelled a bit too enthusiastically.

The master trainer also questioned his own decision to apply a hood. He revealed Moore felt the headgear made the horse slow to respond and slightly confused when asked to quicken, meaning the penny dropped a fraction too late.

The Ballydoyle team will now monitor the horse's recovery before finalising plans with his owners. O'Brien maintains unwavering belief in the colt's natural speed and suggested a return to sprinting might unlock his true brilliance. A late £30,000 supplementary entry for the Guineas remains a possibility if they stick to a mile, but dropping back to six furlongs for Haydock's Sandy Lane is now firmly on the table.

With Albert Einstein's Newmarket status hanging in the balance, O'Brien's other major Guineas hopes are stepping into the spotlight. Puerto Rico, who capped off a brilliant juvenile campaign with successive Group One victories in France, is currently in pole position for the May 2 feature.

Stable confidence is undoubtedly high. O'Brien reported the pacey colt progressed with every run last season, wintered beautifully and is thriving in his current track work.

Meanwhile, Breeders' Cup hero Gstaad, who would also require a £30,000 supplementary fee to run at Newmarket, is now likely to be rerouted. O'Brien indicated the straightforward and versatile colt will probably head to ParisLongchamp for the French 2000 Guineas, leaving the Newmarket stage clear for Puerto Rico.

O'Brien also holds a powerful hand in the 1000 Guineas market, responsible for the top two betting choices in Precise and Diamond Necklace. A recent spring setback had thrown Precise's participation into doubt, but the trainer delivered an optimistic update on her recovery.

Following a highly satisfactory piece of recent work, O'Brien is confident she is winning her race against time to be fully fit. If Precise gets the green light for the Newmarket classic, the plan is to divide and conquer by sending Diamond Necklace across the Channel to contest the French equivalent.

Image: Pat Healy Photography