Erik ten Hag’s side suffered a Champions League set back as they let a two-goal lead slip in Turkey, with Onana partly culpable for the hosts’ first two goals.
It continued a difficult start to life in Manchester for the Cameroon international, who was signed from Inter Milan in the summer.
Onana was immediately installed as Ten Hag’s first choice goalkeeper, but finds his place under severe scrutiny after a series of high-profile errors.
Carragher believes that the 27-year-old has developed a reputation as a “liability” that will be difficult to shift.
“Unfortunately for Onana, at the start of his United career he has been responsible for turning victories into draws, and draws into defeats,” Carragher wrote in his Telegraph column.
“United’s perilous Champions League predicament is a direct consequence of his errors. Onana cost the team home and away against Galatasaray and was poor against Bayern Munich in the opening group game. Yes, he made a last minute penalty save against Copenhagen at Old Trafford, but the numerous minuses far outweigh that one positive.
Andre Onana had a difficult evening at Galatasaray— (EPA)
“The performance in Turkey was unacceptable for a Manchester United goalkeeper. You would not expect an Under 18 keeper to make the basic handling error for Galatasaray’s second goal. If a youth keeper was promoted and played like Onana on Wednesday evening, he would probably never feature for the first team again.
“Onana has cost United too many cheap goals. The hope that the worst was behind him after a poor start to his Old Trafford career has been blown out of the water and Wednesday was a huge step backwards. Onana has already developed a reputation for being a liability. That will take a long time to overcome and reverse.”
Onana replaced David de Gea as Manchester United’s No.1, with the Spaniard departing the club in the summer after more than a decade at Old Trafford.
De Gea similarly endured a tough start in England, and was displaced by Anders Lindegaard during his first Premier League season. The Spanish shot-stopper subsquently established himself as one of the world’s top goalkeepers.
David de Gea departed Manchester United earlier this year— (Getty Images)
Carragher still thinks that Ten Hag made the right call to end De Gea’s tenure, but fears the Dutch manager may have made an error in trusting Onana as his successor.
“The time was right for David de Gea to leave Old Trafford last summer,” the former Liverpool defender explained. “He gave sterling service, but it was understandable the club looked for a younger keeper, presumably on a much lower salary. Ten Hag also wanted someone more adept with his feet.
“Recruiting an inferior keeper makes no sense, however. Ten Hag cannot disguise the reality that United have suffered because of Onana’s avoidable mistakes.
“It is admirable for a manager to stand by a player in the face of mounting criticism. There is also a fine line between that being a sign of strength or weakness. Onana must massively improve in the coming weeks and months, otherwise the derision will shift from an erratic keeper to the manager who keeps picking him.”