Cambridge's preparations for the Xchanging Boat Race suffered a significant setback yesterday, when Shane O'Mara, the stroke, was withdrawn on medical advice only three days before the race. O'Mara, a 25-year-old land economy student from Florida, was replaced last night in the Blue boat by Ryan Monaghan, the stroke of Goldie, the second boat, and a fellow American.

Cambridge did not take their scheduled 2.30pm outing as news of O'Mara's unexplained illness emerged, but the new-look crew went for a twilight training session three hours later and Duncan Holland, the head coach, expressed satisfaction with the way the crew responded.

“Shane fell ill overnight and we decided to withdraw him,” Holland said. “It is not life-threatening and shouldn't affect his long-term rowing. I'm happy Ryan will be a direct replacement.”

Monaghan, 23, took up rowing at the age of 16 after suffering persistent joint injuries through playing football. He rowed for Cornell University during his primary degree.

It is tough luck for O'Mara, but because he is in the first year of a three-year degree there may be other Boat Races. For this year's Cambridge crew, however, it is a severe blow to lose a United States World Cup rower who holds all the US junior records for single sculls.

Although adversity can make a crew stronger - Oxford won in 1992 a few weeks after the death of a squad member - such a late withdrawal, especially of the stroke, who sets the rhythm of the boat, is bound to unsettle a team. In 2003, Wayne Pommen, of Cambridge, broke a wrist in training a couple of days before the race when the boat collided with a Port of London launch. Cambridge lost the race by one foot. A year later, Sam McLennan, the Oxford president, pulled out with a stress fracture of his back two weeks before the race, which Cambridge won.

However, Dan O'Shaughnessy, the Cambridge president who will row in Goldie, said the loss of O'Mara would not affect the team too badly. “Morale will be fine,” he said. “Although the Blue boat was settled months ago,

we've been training and rowing both boats together. Winning the race is still our goal.”

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