Doctors have eased the fears of South African fast bowler Mfuneko Ngam about the possible implications of a broken thigh bone.

The 21-year-old will miss the team's first tour of the West Indies due to the injury, which was discovered earlier this month.

It is the third stress fracture he has suffered in as many years and team physio Craig Smith feared Ngam's "skeletal strength" was lacking due to a "dietary or genetic insufficency".

Blood tests were ordered and Dr Andre Killian, a member of the United Cricket Board's medical committee, says there is no sign of inherent weakness in his bone structure.

"We did a bone density test, which showed all his bones to be of normal density, as well as various blood tests which all came up normal. The injury has been caused by over-exertion," he explained.

Ngam is seen as the heir apparent to South Africa's record wicket-taker Allan Donald and produced deliveries clocked at 147kph during the recent home Test series against Sri Lanka.

The injury could take up to 12 weeks more to heal and he will then need several weeks of rehabilitation and training to regain fitness.

"Ngam has a long career ahead of him. It is not worth rushing him back for this tour," Dr Killian added.

The selectors will name South Africa's tour squad on 17 February. They will play five Tests and seven one-day internationals in the Caribbean between March and May.