Tonali's ban was announced by the Italian Football Federation on Thursday but FIFA were yet to ratify the decision and Newcastle hoped the midfielder would be available to face Wolverhampton Wanderers on Saturday.
But FIFA have now put their seal on the Tonali's ban, which came about from betting breaches while a player of AC Milan.
The 23-year-old will miss the rest of the season for Newcastle as well as EURO 2024 should Italy qualify.
''Sandro Tonali has been banned from competitive football for ten months, as effective from Friday, 27th October 2023, following illegal betting charges by the Italian Football Federation (FIGC),'' Newcastle said in an official statement.
''FIGC's sanction includes an overall 18-month ban, with eight months commuted as the player participates in a therapeutic plan and educational programme in Italy consisting of 16 commitments.
"On the evening of Friday, 27th October, Newcastle United received confirmation that FIFA has endorsed FIGC's sanction to be applied worldwide, meaning
Sandro will be eligible to return to competitive football from Tuesday, 27th August 2024.''
Tonali joined Newcastle from AC Milan this summer for £55m and has scored once in 12 appearances across all competitions.
