Saudi Arabia's King Abdullah has appointed the second deputy prime minister to oversee the Hj pilgrimage, the state news agency reported on Saturday, a day after doctors ordered rest for the ruler due to a slipped disc.
Nayef bin Abdulaziz Al Saud, also the Interior Minister, is to oversee the annual haj, when some two million Muslim pilgrims will gather in the holy city of Makkah.
King Abdullah is estimated to be 86 or 87-years-old.
Prince Nayef, thought to be about 76, was appointed second deputy prime minister in 2009, a move which analysts said places him in a strong position to become crown prince or king one day.
Nayef, a half-brother of the king and full-brother of the crown prince, has been in Makkah this week, supervising security arrangements for the Haj.
Crown Prince Sultan, the king's half-brother who is also in his 80s, has been abroad for unspecified health treatment for much of the last two years and diplomats in Riyadh say he has not resumed full duties. He is outside the country after leaving for what was described in August as a holiday in Morocco.