Zlatan Ibrahimovic called an end to his Manchester United career because the club were knocked out of the Champions League, according to his doctor.
Last week, the Premier League giants confirmed the striker's departure.
Not long afterwards, MLS side Los Angeles Galaxy announced the signing of Ibrahimovic, who had spent just under two years at United.
The 36-year-old was a key figure last season at Old Trafford, but a knee injury, which required surgery, towards the end of the campaign hampered his progress.
After returning to action in November, Ibrahimovic extended his deal at United, but struggled for game time under Jose Mourinho, making just five league appearances.
Dr Freddie Fu Ho-Kueng, who carried out surgery on Ibrahimovic's knee, has suggested that the striker left United because they were ousted from the Champions League at the last-16 stage by Sevilla.
"[Ibrahimovic] and the coach get along well. He liked Manchester United, he's a hero before the injury," Fu told the South China Morning Post. "His idea was to see if we can go back and win more titles, especially the Champions League.
"After United lost to Sevilla, I think his decision, in my opinion, was that maybe that was it. This is my feeling. United won't be able to catch up with Manchester City in the Premier League either. Maybe they can win the FA Cup which is good but not as good as the Champions League.
"He did everything else pretty much, won every major thing. Unfortunately they lost to Sevilla. I think he would have stayed longer, but he didn't tell me that."
Ibrahimovic has never won the Champions League in his career.
