City are confident the 19-year-old forward, who arrived in England last week, will be cleared to play but it is understood they only have until Friday to sort out any remaining red tape, says the Daily Mail.
Gabriel is in England acclimatising to his new home with his mother and two friends while he wait to make his City bow.
Pep Guardiola thinks the latest addition to his squad will be ready for first-team action soon despite Jesus' long break in Brazil over the Christmas period.
"He was three weeks to one month off on holidays but he played two friendly games," said Guardiola. "He rested, he needed that."