Singapore-based Glen Boss will take the ride on Darren Weir's galloper.

Williams knows that whatever happens this weekend, he is in for a fierce challenge for the remaining three months of the season in the battle to retain his Melbourne metropolitan jockeys' premiership from young apprentice Beau Mertens, who has his eyes set on history.

Mertens, 20, who is also out of action this weekend through suspension, is aiming to become only the fifth apprentice since the war to win the Melbourne jockeys' premiership following Geoff Lane in 1960, Darren Gauci in 1984-85-86, Damien Oliver in 1991 and 1993 and the now-retired Nick Ryan in 2005.

Mertens' tally for the season is 50, four less than Williams, who will not be able to add to his total of 55 until the pair resume riding in the city at the Flemington Anzac Day meeting next Tuesday.

The statistics show just how hard it is for apprentices to take the title.

Many have run prominently in the championship race; in recent years Patrick Moloney, Chad Schofield and Jason Maskiell have been close to the top while still claiming an allowance. But neither they, nor the likes of the well-established group 1 jockey Damian Lane, could win the championship in the early years of their career.

However, with far more racing these days and trainers happier to put up claiming apprentices, don't bet too heavily against Mertens succeeding, despite the youngster copping an eight-meeting suspension last Saturday after being disqualified in Caulfield's opening race.

Mertens, the son of former jockey Peter, didn't let the disappointment upset him.

He went out later in the afternoon and booted home another two winners for the powerful Lindsay Park operation of David and Ben Hayes and Tom Dabernig.

That he is teaming up with the Hayes/Dabernig operation is a testament to the high regard in which he is held by the champion trainer, who has also nurtured the career this year of another top apprentice, Regan Bayliss.

The latter, who rode out his claim earlier in the season and scored his first group 1 success for the stable aboard Redkirk Warrior in the Newmarket last month, is serving a lengthy suspension incurred in Sydney during the Championships.

Mertens, who can still claim 1.5 kilograms in the city, has filled the gap with aplomb.

Mertens' ability to reduce a horse's weight will ensure such a polished performer is in great demand during the winter months when the tracks soften and every kilogram counts on the heavier ground.

Williams, who was outed on a careless riding charge on Monday's Sandown card after winning on Lopartega, has spent much of the month riding interstate and is likely to be in demand during the Brisbane and Adelaide carnivals in May and June as well, so Mertens may never have a better chance of running down his senior rival.

Dwayne Dunn is seven behind on 43 winners, so he can't be discounted, but it would look difficult for another apprentice, Ben Allen, on 39, to make up the ground.

???"I am getting close but I won't count my pennies too early," Mertens says. "There's still a few months left to go.

"I am not going to go the early crow. Whatever happens happens. If I can keep going the way I am going I will be close. It's a bit shattering to get suspended for a week, but I am sure I will bounce back."

He acknowledges the support he has been getting from the Hayes stable as a big factor in pushing his title claims.

"I am just putting in a bit of work for them, going to trials every Friday, doing a bit for them there and in the week I do a bit of track work for them whenever they need me. I went to Euroa [Hayes' country Victorian property] a few weeks ago and did a couple of gallops for them.

"It's definitely worth doing the hard yards because they have the horses and they are quality, too. When the big hoops can't get in there I will swoop in there and sneak a couple in."