South Africa off-spinner Johan Botha has been suspended from bowling after his action was deemed to be illegal.
Botha is seen as a long-term spin option by the Proteas
The 23-year-old was reported during the third Test in Australia last month and his off-break and "doosra" deliveries were analysed by expert Bruce Elliott.
Professor Elliott ruled he extended his elbow beyond the 15% allowed under International Cricket Council rules.
Botha, who has played in one Test and 10 one-dayers, cannot bowl for his country until further tests clear him.
If he returns and is found guilty of having an illegal action within 24 months he will be automatically banned for a year.
ICC general manager Dave Richardson said: "The independent report has identified excessive levels of straightening.
"It is now up to Johan to remedy the concerns that have been identified.
"Johan is a young player and there is nothing to stop him making a successful return to international cricket with a remodelled action."
Botha started out as a medium-pacer in domestic cricket, but was persuaded by Proteas coach Mickey Arthur to take up slow bowling.
He proved expensive at international level but, amid a dearth of quality spin bowlers, is seen as the long-term successor to Nicky Boje.
Cricket South Africa chief executive Gerald Majola said he accepted the findings and is confident Botha will soon be bowling again for the Proteas.
"We will do all in our power now to assist him to correct his action so that he can continue his promising career," he said.
"We will ask the Sports Medical and Science Institute in Cape Town to analyse the ICC's findings and assist Johan to remedy his action.
"He will then be tested again, and we hope to have him in action as soon as possible."