Charlie Appleby says he dare not think of Pinatubo's ability to stay the mile and a half of the Investec Derby, but is now more comfortable that the mile of the Qipco 2,000 Guineas will be his minimum requirement at three.
Pinatubo conserved his stranglehold over the ante-post market for the Guineas with what was ultimately a comfortable defeat of Arizona in Saturday's Dewhurst Stakes, with the unbeaten colt no bigger than 5-4 for the first Classic of 2020.
Pinatubo also heads the betting for the Derby and, although he has yet to race over further than seven furlongs, Appleby sees the mile at Newmarket as just the starting point.
Speaking in the Racing Post's Monday Jury, Appleby said: "A starting point over a mile will be perfect for him and I see no reason why a mile and a quarter shouldn't be within his compass.
"Most importantly, we're confident he'll get the mile no problem, and from thereon once we've got through the Guineas we can start to map out a plan."
Pinatubo was sired by Shamardal, who has yet to produce a Derby winner, so Sheikh Mohammed could be tempted by Epsom should his super colt land the Guineas.
"Pedigree-wise he's entitled to get a mile and a half - his dam Lava Flow saw the trip out well so you've got that to take into consideration," said Appleby, when talking on RTV's Luck on Sunday show.
"The attribute he takes to seeing out the trip is he's so relaxed, a jockey can put him where he likes in a race.
"As a rule in the first half of a race he's generally asleep and off the bridle, it's not until he comes to the crucial part that this fellow starts to wake up.
"He has the attributes to be able to get the trip. I see him probably as a ten-furlong horse, but maybe that's because I'm not being brave enough to say he's a mile-and-a-half horse."
Pinatubo is a best-priced 7-1 for the Derby, with Beresford Stakes winner Mogul his closest market rival at no bigger than 10-1.