Onana had, in theory, ended last season as United’s number one goalkeeper given he started the Europa League final defeat by Tottenham.
However, after injuring his hamstring at the start of pre-season training, he missed all United’s warm-up games and was overlooked for their opening three Premier League matches, when Bayindir was chosen.
Onana did start the shock second-round EFL Cup defeat by League Two Grimsby last month, when he was at fault for the Mariners’ second goal.
The 29-year-old was signed from Inter Milan for £47.2m in 2023, with then United boss Erik ten Hag keen to be reunited with a goalkeeper he first worked with at Ajax.
Onana has rarely looked comfortable, though, and the decision to bring him in to replace four-time club player of the year David de Gea has repeatedly been questioned.
A succession of mistakes led to Onana being dropped for the Premier League defeat at Newcastle on 13 April, although he was recalled for the chaotic 5-4 Europa League quarter-final win over Lyon immediately afterwards.