O'Brien reports the Dewhurst winner to have grown considerably and that the trip should prove no problem to him in the first colts' Classic.
"He's doing everything unbelievably well at the moment. From this coming weekend it's three weeks to the 2000 Guineas, so the next two weeks will be key, but he's doing unbelievable at the moment," said O'Brien of the champion European two-year-old.
"He looks a different creature altogether. He's big, he's powerful, he has a good mind and he's a great mover. He's physically very big, but he's not a big long yoke, he's compact, strong and well made.
"In terms of trip, I always thought he'd be fine at a mile and maybe up to a mile and a quarter. I wouldn't be sure about a mile and a half for him, but his temperament will give him every chance if he's ever asked to try it."
Caravaggio won the Coventry Stakes and the Phoenix Stakes before missing the back-end of the season, but O'Brien is not as confident about him staying a mile. Nevertheless, the French Guineas is on his agenda.
Speaking in a stable tour for www.attheraces.com, the Ballydoyle trainer said: "He's working great. We brought him to Naas to work the other day and he's plenty fit so we didn't feel we needed to do a lot more with him.
"We're just not sure about him getting a mile. He's a very fast, very quick horse. What is very unusual about him if you go back and watch footage of him is that when he quickens, he nearly knocks himself over.
"A lot of those sprinters are about relentless speed, but this fella can really quicken. He has big shoulders, a big backside, a great head and he's long too. Physically, he looks more like a sprinter.
"We are training him for the Poule d'Essai des Poulains at the moment, but if we see anything that makes us think that asking him to try a mile is the wrong thing between now and then, we'll run him elsewhere.
"He bends his knee a bit, but the ground probably isn't a big issue for him and dirt would probably be fine for him too."
O'Brien also mentioned that Yucatan and Capri, third and fourth in the Ballysax Stakes last weekend, would head for the Derrinstown Derby Trial, with Orderofthegarter heading for the Irish Guineas and Lancaster Bomber a possible for either the Kentucky Derby or the Preakness.
