Onana performed well below the expectations of fans at Old Trafford during his two seasons with the Red Devils.
The Cameroonian goalkeeper was largely blamed for the team’s 15th-place finish in the English top flight last season.
Onana was brought in from Inter Milan as a replacement for veteran goalkeeper David De Gea.
The Cameroonian has now made a late move to Trabzonspor on a season-long loan, as Turkish goalkeeper Altay Bayındır takes his place.
Onana only featured in the Carabao Cup second-round exit at Grimsby Town this season.
Addressing the press ahead of the Red Devils’ meeting with Manchester City on Sunday, Amorim said: “Onana did great at Inter but as a club now we needed a change.
“Sometimes it’s hard to point why, the performance, the moment, the bad luck in some moments was hard on him.
“I wish André all the very best.”
