A South African rugby player was in police custody last night over an alleged assault that left a US player with spinal injuries during the World Rugby Classic.US team manager Tim Kluempers said 34-year-old fly half Leif Gibson may never play again as a result of the injury, which allegedly occurred “off the ball” during Saturday night’s game.South African prop Robbie Kempson, 38, was arrested after the incident, which occurred around 15 minutes into the match at the National Stadium in Devonshire.According to Mr Kluempers, a Springboks player ran into Mr Gibson’s back from behind when his back was turned.Mr Gibson was helped off the pitch before collapsing and being taken to King Edward VII Memorial Hospital for treatment.According to Mr Kluempers, he is due to fly to Houston today for further medical attention. The manager was unable to be specific about the nature of the injury, but said Mr Gibson has “severely injured his back” and been fitted with a neck brace to travel home in.South Africa ended up beating the US by 43 points to ten and the US are now set to meet France in the Plate Semi Final on Wednesday.Asked why the police made the unusual move of investigating something that happened on the field of play, Mr Kleumpers replied that it was the player’s decision.“He said if it happened in the course of play, in a tackle or ruck, that’s understandable. It’s the risk we take. When it was in off the ball play, that was not necessary.”Mr Gibson is on his first ever tour with the US team. He was resting at the team hotel yesterday evening, as arrangements were made to fly him home.“Thank God he can still walk and get around,” said the team manager.“It’s frustrating that something like this happens off the ball and away from the play. We have rallied around and are supporting him.”Mr Gibson has told his team mates he wants them to carry on with the tournament.“We still have a game ahead of us and he has expressed to the team (that we should) go out and beat the French,” said Mr Kluempers.A police spokesman said: “Police are investigating a report of assault that took place Saturday night at the World Rugby Classic.“As a result, a man has been arrested in connection with an off ball assault that took place during the USA/South Africa match. Police are appealing for witnesses, specifically anyone who may have video images of the assault, to contact Sergeant Derek Berry on 295-0011.”Rugby Classic President John Kane declined to comment.South Africa team manager Mark Wood said yesterday afternoon that he did not have any information about the incident, and would have to talk to other members of the squad last night. Efforts to reach him for comment after that proved unsuccessful.