Murray's Sun has taken his trainer on the rollercoaster ride of a lifetime and Bridget Jones says he is ready to prove the naysayers wrong.

With only 24 starts in a career marred by injury, Jones says the gelding still enjoys racing.

"He's definitely got it in him and he's definitely still trying," Jones told AAP.

Jones said Murray's Sun was his own worst enemy because he liked to get back and find his feet early in a race which meant he was "always playing catch-up".

But she says her relationship with the gelding has been a significant one.

"He's just taken me on the most wonderful rollercoaster ride," Jones said.

"He's the first horse I bought to train in Australia, for $900 and I ended up in Sydney (when) I was just hoping for a little country horse to play with."

Jones has had the horse she affectionately calls `Sunny' since he was a yearling but his career has progressed in fits and starts, plagued by back problems, bone cysts in both back hocks, and a virus.

"This is the longest prep I've had with him in his whole career - the most races we've had in one go before is four," Jones said.

"He's running very big races but he's also been carrying big weights."

Murray's Sun carried 57.5kg in Sydney last start and prior to that lumped 61kg in two unplaced runs at Dubbo and Muswellbrook.

He will have just 52kg in Saturday's International Animal Health Handicap (1400m) at Rosehill after apprentice Sam Clipperton's two kilo claim.

"The weight will make a difference ... that's why I put Sam on him - to give him every ounce off that I can," Jones said.

Jones' return to horses has been a circuitous one.

She arrived in Australia over 20 years ago from the UK to work in an opal mine in Lightning Ridge, before finding work as a strapper for Mike Williams.

After not having ridden a horse for 12 years, Murray's Sun was Jones' first purchase to train.

"He's the horse of a lifetime, one most trainers dream of having because of his sheer brilliance and speed," Jones said.

"If he hadn't had the back problems I think he would certainly have been a Group horse."

She acknowledges he faces a strong field on Saturday, but says Murray's Sun is finding his stride again.

"There are people out here saying, `oh he can't do it', and I just love to prove them wrong," she said.

"I'm sure he can, and he loves what he's doing.

"If he didn't, I wouldn't be asking him to race."