Sharrock says that doesn't worry him at all today.
"I know it is unusual stepping them up from 1400m straight to 2000m but I am sure he will handle it," Sharrock told the Herald yesterday.
"He is a very relaxed horse, as we saw at Trentham last start, and he has hit the line hard in all his runs.
"So I don't think the distance will be a worry. I know you never really know until they do it, but he will prove that this week and then we can press on to the Avondale Guineas."
Sharrock says if Shamus is to be a Derby runner, he will need that extra run over the 2100m of the Avondale Guineas as much for the Ellerslie experience as race fitness.
"I am a great believer if you are going to a major race at Ellerslie, especially with a younger horse, you need to give them a look around to get used to the undulations of the track and even the signage."
Shamus will have a new rider today, with Leith Innes taking over from stable apprentice Hazel Schofer, Innes having ridden Wahid to win the 2006 Derby for Sharrock and the same owners as Shamus.
Shamus is the best drawn of the favourites at barrier one today and could even secure the trail, with Field Of Gold, who led and was only collared late by Dark Destroyer in the Auckland Guineas, drawn two.
If the pair end up in a lead-trail scenario and get away with anything like easy mid-race sectionals, it will not only aid Shamus in getting his first attempt at 2000m but make it harder for those back in the field.
That could include The Perfect Pink from barrier 10 and Dark Destroyer from nine, both of whose trainers realise today's race is potentially tricky.
Jamie Richards says The Perfect Pink has come on from her narrow last-start defeat by La Crique but the barrier could see her having to come wide late in the race in her toughest test against the boys, so her $2.50 opening quote looks too short.
Co-trainer Andrew Scott says he and partner Lance O'Sullivan have taken the blinkers off Dark Destroyer in an effort to teach him to settle first time over ground.
"We want to see him get into a rhythm and learn to conserve energy in this race, which will help him heading forward to the Derby," says Scott.
"So while we would love to win this, it isn't the grand final, and from that draw, we could be standing some good horses a start."
● Railway winner Entriviere will also be at Te Rapa today but won't be of much use to punters.
The speed freak mare will highlight an open catchweight trial at 1.12pm which also features comeback Group1 winner True Enough, Sound, White Noise and last-start Telegraph placegetter Mascarpone.
Entriviere and Mascarpone are using the trial to prepare for Saturday week's star-studded BCD Sprint.