The 21-year-old will spend the season with Getafe after United decided to cut ties with the forward following a six-month investigation into his conduct.
A criminal case against Greenwood following his arrest on suspicion of attempted rape and assault was discontinued in February.
Greenwood has a contract at Old Trafford until 2025 but is not expected to play for the club again.
The striker hadn't played a competitive game since Jan. 22, 2022. He had been suspended by United for the past 18 months but was undergoing an individual training programme away from the club to prepare for his return to football.
A small section of Osasuna fans chanted negatively at Greenwood during the match.
"The chants [against Osasuna] were very bad and the chants against Greenwood were very bad too," he said. "He is a player who, in the end, the justice system had its say.
"He is a very good player. But if we talk about chants, we should talk about all the chants, not just some."