Balshaw will take no further part in the tour and will fly home later today.
England have been able to deliver a more positive fitness bulletin on other players who were injured during a punishing contest at Vodacom Park.
Jonny Wilkinson, who went off with a facial laceration and a bruised lower back, is expected to train later this week together with flanker Andy Hazell, who sustained bruising to his left knee.
Hazell's fellow flanker Pat Sanderson underwent checks on his neck, but England say that has settled well and he will be fit to train tomorrow.
Stomach virus victim David Strettle, meanwhile, was discharged from hospital yesterday and has rejoined the squad, with Andy Farrell and Peter Richards continuing their recovery from the same virus that meant they missed Saturday's game.