Portuguese superstar Cristiano Ronaldo faces a wait to make his Al Nassr debut because the Saudi club have exceeded their quota for foreign players, club sources told AFP on Thursday.

When he was unveiled with great fanfare on Tuesday, the 37-year-old said he was keen to play as soon as possible, starting with Thursday's home game against Al Ta'ee.

But Ronaldo, whose deal is worth an estimated 200 million euros to June 2025, is Al Nassr's ninth foreign player -- one more than the eight allowed by Saudi football authorities.

The game at the 25,000-capacity Mrsool Park was eventually postponed for a day until Friday over "electrical faults" caused by heavy rain, the Saudi Pro League said.

"Al Nassr has not registered him yet because there is no vacancy for a foreign player," one Al Nassr official, who did not want to be named because he was not authorised to speak to media, told AFP.

"A foreign player must leave to register Ronaldo, either by selling or by terminating the contract by mutual consent," the official added.

Al Nassr's foreign contingent includes Colombian goalkeeper David Ospina, Brazilian midfielder Luiz Gustavo and forwards Anderson Talisca of Brazil and Vincent Aboubakar of Cameroon.

Saudi reports said Uzbek midfielder Jaloliddin Masharipov was most likely to make way for the five-time Ballon d'Or winner and Champions League record scorer.

A second club source confirmed that Ronaldo was not registered as of Thursday afternoon local time.

"There are ongoing negotiations to sell one of the players, but they have not reached their final stages yet," he said.

Al Nassr's first game since Ronaldo's arrival will now be held on Friday at Mrsool Park, in the capital Riyadh, after an engineering report raised safety concerns, the Saudi Pro League said.

The stadium "was unable to host the match, due to the heavy rain that led to electrical faults in lighting the stadium and the gates, based on the engineering report, and in the interest of the safety of the players and the attendees, the match was postponed", a statement said.

Mrsool Park, where Ronaldo was unveiled to fireworks and deafening cheers from a capacity crowd on Tuesday, was sold out once again for Thursday's scheduled game.

Both club officials refused to confirm whether Ronaldo still needed to serve a two-match English Football Association ban issued in November for hitting a mobile phone out of a teenage fan's hand after Manchester United, his club at the time, lost to Everton.

The Saudi Football Association referred questions about the match ban to Al Nassr.

On Tuesday, the Portuguese forward said he was looking for a new challenge by coming to Saudi Arabia, adding that he had received offers from around the world.

"I'm a unique player. It's good to come here, I broke all the records there (in Europe) and I want to break a few records here," Ronaldo said.

Amnesty International urged him to speak out about human rights issues in the deeply conservative monarchy, calling his move part of a "wider pattern of sportswashing", or using sport to deflect criticism.