Hong Kong-based Brett Prebble has answered an eleventh hour call up to ride gun colt Smart Missile in Saturday's Group One Sir Rupert Clarke Stakes at Caulfield following an injury to Glen Boss.In a dramatic morning, Boss fractured the humerus in his left arm when he fell from 2010 Golden Slipper winner Crystal Lily in a jump out at Flemington on Friday.Crystal Lily collapsed and died while Boss was taken to Melbourne's Epworth Hospital where scans revealed the fracture.Smart Missile's trainer A

Hong Kong-based Brett Prebble has answered an eleventh hour call up to ride gun colt Smart Missile in Saturday's Group One Sir Rupert Clarke Stakes at Caulfield following an injury to Glen Boss.

In a dramatic morning, Boss fractured the humerus in his left arm when he fell from 2010 Golden Slipper winner Crystal Lily in a jump out at Flemington on Friday.

Crystal Lily collapsed and died while Boss was taken to Melbourne's Epworth Hospital where scans revealed the fracture.

Smart Missile's trainer Anthony Cummings mounted a search for a replacement with half a dozen riders, including the Singapore-based Joao Moreira, making the short list.

But after discussions with owner Eduardo Cojuangco, Prebble was deemed the man for the job.

Ironically, Prebble made a special trip back from Hong Kong to win the Golden Slipper aboard Crystal Lily.

He has never ridden Smart Missile and he won't get his first look at the three-year-old until race day.

The colt can be a handful. He was a dramatic late scratching for this year's Golden Slipper after getting hung up on the barriers and he ran out in the straight last start when giving chase to Manawanui in the Group One Golden Rose, eventually going down by a short neck.

Adding to Prebble's task, Smart Missile will have his work cut out from the outside barrier in the 17-horse field.

Prebble, who forged a successful riding career in Melbourne before moving to Hong Kong, was due to arrive in the southern capital on Friday night.

In spite of the dramas, Smart Missile remains the $3.50 favourite to land his first Group One win in the 1400m feature.

He also heads betting for the Caulfield Guineas (1600m) two weeks from Saturday and Prebble's manager Glenn Darcy says the hoop is also available for that ride.