Dual Derby winner and leading Melbourne Cup contender Rebel Raider has suffered a major leg injury, placing his racing career in jeopardy.Trainer Leon Macdonald said X-rays taken on Monday showed the five-year-old entire had fractured a sesamoid but he was uncertain where or how the injury occurred."He is definitely out of the spring and his (racing) career is in grave danger," Macdonald said.Rebel Raider only beat one runner home in the Makybe Diva Stakes at Flemington last Saturday week with h

Dual Derby winner and leading Melbourne Cup contender Rebel Raider has suffered a major leg injury, placing his racing career in jeopardy.

Trainer Leon Macdonald said X-rays taken on Monday showed the five-year-old entire had fractured a sesamoid but he was uncertain where or how the injury occurred.

"He is definitely out of the spring and his (racing) career is in grave danger," Macdonald said.

Rebel Raider only beat one runner home in the Makybe Diva Stakes at Flemington last Saturday week with his performance put down to his first experience on a heavy track.

Macdonald, who trains in Adelaide in partnership with his son-in-law Andrew Gluyas, said he was not initially concerned and it was all systems go for this week's Underwood Stakes.

"He pulled up a bit short after Flemington and there was a little swelling which we treated," he said.

"But Andrew rang me from Melbourne yesterday and said he wasn't right so we X-rayed him and that's when the injury showed up.

"We don't when or where it happened.

"He's back home in Adelaide now. He's fine and happy within himself otherwise."

It was a bitter blow for Macdonald and the owners of Rebel Raider, coming just days after the anniversary of his withdrawal from last year's Cup.

Rebel Raider was one of the early favourites in 2009 but suffered a leg injury in trackwork a day after weights were declared in September.

A striking son of the unbeaten Zabeel stallion Reset, Rebel Raider scored an upset in the 2008 Victoria Derby when he beat odds-on favourite Whobegotyou.

The following autumn he failed in Sydney, showing a dislike for racing in the right-handed direction and his AJC Australian Derby bid was aborted.

Back home in South Australia he put in a dashing performance under regular partner Clare Lindop to win his home town Derby and earn early favouritism for the Melbourne Cup.

He recovered from last year's injury with the aid of surgery and a lot of work on the water-walker and had a short autumn campaign to keep him fit.

He announced he was ready to take on the best again with a brilliant win over 1200 metres in the Spring Stakes at Morphettville on August 14 to once again jump into calculations for the Melbourne Cup.

His 20 starts have netted six wins from 1200 to 2500 metres and four placings with his earnings topping $1.4 million.

Rebel Raider had been around the $21 mark to win this year's Melbourne Cup.