The decision was made by Ruben Amorim to calm the turmoil surrounding the 29-year-old Cameroonian.
Onana has had a week to forget. After a bust-up with Nemanja Matic in the build-up to the first leg of the Europa League quarter-final against Lyon, he was directly involved in the French club's two goals.
Under a lot of criticism, Onana will now have some time to recover away from the spotlight. On Sunday morning, The Athletic revealed that Amorim had decided not to call him up for the Newcastle game as a measure of protection.
Altay Bayindir will thus make his Premier League debut, with Tom Heaton as back-up. It will only be the Turkish goalkeeper's seventh game this season, having played in two Europa League matches, one FA Cup match and three League Cup matches.
Signed in 2023 from Inter, Onana has had a bumpy time, to say the least, at United. He is still a regular starter and has made 94 appearances over the last two seasons.