Manchester United left-back and England international Luke Shaw revealed he nearly lost his leg after a breaking it in two places against PSV Eindhoven in 2015.
"I had a lot of complications with my leg and that was the really hard moment for me in my career," Shaw said on Tuesday at a news conference. "No one knows but I was really close to actually losing my leg. I never knew that until six months later when the doctor told me.
"At the time, they were thinking about flying me back and if I'd have flown back, I would probably have lost my leg because of the blood clots and stuff.
"I've got -- I don't want to talk about it too much -- two scars down the side of my leg where they had to cut it open and pull them out because of how severe it was."
The 23-year-old was last week named in the England squad for the first time in 18 months for the Nations League match against Spain on Saturday and the friendly with Switzerland on Tuesday.
His return to the international fold follows a strong start to the season in which he has played every minute of United's opening four games after he struggled to get into the team last term, with manager Jose Mourinho critical of Shaw's attitude.
Shaw believes Mourinho was right to criticise him and said the Portuguese had been key to his international recall.
"I think he got frustrated with me because he knew I could do better. When I look back, maybe he was right," Shaw said when asked about how he was treated by the United manager.
"It was a tough few years but it made me stronger mentally. I wanted to prove to him I could do what he said I couldn't. I had a chat with the manager before the season and he said he wanted me to stay.
"I've matured. You could say I've gone from a kid to a man. I know what I need to do to push myself. I want to play for Manchester United, stay there and prove my worth to the team."
Shaw was one of the most expensive teenagers in world football when he moved to Old Trafford from Southampton for £27 million pounds ($34.70m) in June 2014 aged 18, having made his England debut four months previously.
He was a regular in former United manager Louis van Gaal's team until he broke his leg, then missed two months of the 2016-17 season with a groin problem and then twice had operations on his foot.
"But I don't really care about that anymore," said of his injuries. "I feel really strong -- and my right leg is exactly as it was before my leg break."
However, his path to recovery was tough to handle mentally.
"I've seen a psychologist. My leg break was a very tough time," he said ahead of England's first matches since they reached the World Cup semifinals without him in the squad.
Shaw has seven caps but his last appearance was in March 2017 as a substitute in a 1-0 friendly loss to Germany.
He said he was "gutted" to miss out on the World Cup and watching from the outside inspired him to have extra training in Dubai during the close season to get fit for the new campaign.
"All the stick I've had in the last few years has pushed me. I wanted to prove everyone wrong and get back to what I do best. I need games to get fully fit and motivated. I'm feeling back to my old self," he said.
Reuters contributed to this report.