Manchester City defender John Stones says he considered retiring last season as he struggled to cope with recurring injury problems.
Stones spent most of the last campaign on the sidelines due to foot and hamstring injuries.
The 31-year-old made just 24 appearances for City and England before his season ended prematurely in February.
He is fit again and could make his first appearance under England boss Thomas Tuchel in the friendly against Wales on Thursday or next week's World Cup qualifier in Latvia.
"Last season was tough for me, to the point where I thought about stopping," Stones told BBC Radio 5 Live.
"I didn't want to do it. I had had enough of being so professional and trying to do everything right in my power, to then keep breaking down and not having the answers. It was a very difficult place to be in.
"There comes a point where you don't know why it happens and it's even harder when you put in so much effort, or you are ultra professional, to be able to play and be available.
"When that time comes and something happens, it would be easier to say: 'Well, I didn't do X, Y and Z, that's why', but when you do it, it's then mentally challenging. Hopefully I don't go back to that place."
Stones has been unable to make more than 27 appearances in a league campaign for City since signing from Everton in 2016.
He has won six Premier League titles, two FA Cups, two League Cups and the Champions League during his time at the Etihad Stadium.
And the centre-back, who has been in the England squad at five major tournaments, said he quickly realised he couldn't walk away from the sport.
"My emotions were high. I wasn't thinking straight. I don't think deep down I would have ever done it," he said.
"I said years ago when City wanted me to have a new challenge, I said, 'I am going to fight'. That's all I have known since I was a kid – why should I stop that now?
"So yes, there is that fight in me and that winning mentality that doesn't want to stop."
England boss Tuchel gave Stones a watching brief as a non-playing member of his squad for the games against Andorra and Senegal at the end of last season.
It was a gesture of faith that Stones appreciated.
"I love England so much and I love playing for England. Some of the best moments in my career have been playing for England at tournaments," he said.
"And when he said to me, would I come out and be with the guys and continue my training, it was a no-brainer. It was a special moment."