Gabriel Jesus's registration will not be completed in time for Manchester City's game with Everton on Sunday.
City signed the 19-year-old in a reported £27 million deal from Palmeiras in the summer but he remained on loan with the Sao Paulo club -- helping them to the Brazilian title in November.
Asked about Jesus ahead of Sunday's Premier League clash with Everton, Pep Guardiola told a news conference: "He cannot play [because of] papers. When Palmeiras and the FA solve the problems he will be able to play."
Sources have told ESPNFC that the club remain relaxed about the situation and say the required paperwork is almost complete.
Jesus arrived in Manchester on Jan. 3 and has trained with the first team squad as he works his way back to full fitness.
Guardiola said he did not expect the player to take much time to be ready with his last competitive game on Nov. 27 -- the 1-0 victory over Chapecoense that saw Palmeiras win a record ninth Brazil championship.
The Spaniard told a news conference before the FA Cup third round tie with West Ham United last week: "He was three weeks-one month off on holidays but he played two friendly games. He rested, he needed that.
"He has made two training sessions -- this afternoon he will make his first training session with the team.
"We are delighted he is here and what we are looking for is for him to settle as soon as possible, to try to help him to be happy here and to have a good connection with his teammates."
Speaking at The Atlantic Council Global Energy Forum in Abu Dhabi on Thursday, City chairman Khaldoon Al Mubarak stressed the club are not in a rush to put pressure on Gabriel Jesus.
"He's an incredible talent," he said. "When we first started looking at him about a year ago, he was unknown. He wasn't a global name by any means. We were successful in acquiring Gabriel to Manchester City in the summer. Even then he was still relatively unknown.
"He's 19, he's very young, Brazilian, going to Europe and the Premier League and we're very conscious that we need to take care of him all the time and not put too much pressure on him.
"We have a lot of aspirations for him, but we have to be patient. He's 19 and there's still time to adjust."