Champion jockey Glen Boss could be riding again in two weeks despite fracturing his upper left arm in a jumpout at Flemington.Boss, 42, was riding 2010 Golden Slipper winner Crystal Lily in Friday morning's trial when the mare collapsed and died underneath him.Boss' manager Reece Murphy said the three-time Melbourne Cup-winning jockey had fractured his left humerus and was scheduled for surgery at the Epworth Hospital on Friday afternoon."The plan is for him to have a plate or rod inserted," Mur

Champion jockey Glen Boss could be riding again in two weeks despite fracturing his upper left arm in a jumpout at Flemington.

Boss, 42, was riding 2010 Golden Slipper winner Crystal Lily in Friday morning's trial when the mare collapsed and died underneath him.

Boss' manager Reece Murphy said the three-time Melbourne Cup-winning jockey had fractured his left humerus and was scheduled for surgery at the Epworth Hospital on Friday afternoon.

"The plan is for him to have a plate or rod inserted," Murphy said.

"The doctor says the best case scenario, if everything goes well, is that he will be back in two weeks.

"He has been very lucky indeed and we are hopeful of a good recovery."

The fall could not have come at a worse time for Boss who was to ride favourite Smart Missile in Saturday's Group One Rupert Clarke Stakes at Caulfield.

Hong Kong-based jockey Brett Prebble replaces Boss on Smart Missile while replacement riders also have to be found for his other six rides on the eight-race card at Caulfield.

He was also booked to ride the ill-fated Crystal Lily in next Friday night's Group One Manikato Stakes and has been the regular rider of dual Group One winner Shamrocker who is to run in Sunday week's Group One Turnbull Stakes at Flemington.

Crystal Lily's co-trainer Simon Zahra said Crystal Lily suffered a suspected heart attack during the jumpout.

"She was probably halfway through the trial and started to drop out suddenly and then collapsed to the ground," Zahra, who was watching from the grandstand, told ABC Radio.

Zahra said there were no indications that the mare had any health problems.

"She's never had any issues in her whole life, from day one," he said.

"It's an unfortunate incident."

Zahra said it was devastating for everyone involved with Crystal Lily.

Murphy said he got the bad news from a distraught Boss when he rang him not long after the fall.

"He said `I have smashed my shoulder, ring Anthony Cummings and tell him I can't ride Smart Missile'," Murphy said.

He said Boss' left shoulder bore the brunt of the impact.

Murphy said importantly scans of Boss' head and neck came back clear.

Boss is no stranger to serious injury and in June 2002 suffered two breaks in his neck when he fell from a horse in torrential rain in Macau.

Initially it was feared the injuries would be career-ending but after six months in a neck brace he was riding trackwork again.

Now he is one of Australia's most accomplished big-race riders and ninth on the all-time Australian jockeys' list with 74 Group One wins. He won 34 Group One races in four seasons from 2003/04.

His three Melbourne Cups on Makybe Diva made him a household name. He also won the 2005 Cox Plate on the champion mare and finished second on her in a photo-finish in the 2004 Caulfield Cup.

He rode So You Think to win the 2009 Cox Plate and twice landed the Golden Slipper Stakes on Flying Spur (1995) and Sebring (2008).

Among his other Group One winners are Typhoon Tracy, Aloha, Triple Honour, Turffontein, Haradasun, Serenade Rose, Fastnet Rock, Private Steer, Starcraft, Dance Hero, Choisir, Hit The Roof, Sky Heights and Telesto.