For Phil Neville, a successful career with Manchester United and Everton could have been over before it had started.
A six-time Premier League champion, Neville made a total of 505 top-flight appearances.
But he has opened up about how he worried a debilitating illness could shatter his footballing dream early in his career.
"When you have an injury you know the diagnosis, you know the recovery time," says Neville in the 12th edition of "Inside Matters", a series of interviews with stars about the mental challenges they have faced.
"But I got glandular fever when I was 19 or 20, and it was probably one of the scariest moments of my career.
"I lost a stone and a half. I lost all my power and my strength and there was a time when I thought that I maybe wasn’t able to come back from it."
"It's an illness that attacks your muscles, your weight, your power, your strength, and those are the key ingredients to be a footballer.
"I lost a stone and a half. I lost all my power and my strength and there was a time when I thought that I maybe wasn't able to come back from it."
Neville is quick to highlight the importance of his family, including his older brother Gary Neville, and also the significant role that his manager at Man Utd played in his recovery.
Pressure off
"Sir Alex Ferguson was without a shadow of a doubt, at that time, the most influential, crucial person in my life," adds Neville.
"He had total faith and he had total belief that I could come back from this really, really bad illness.
"He said, 'We will give you the best care. We will give you the best time in terms of... there is no timeframe for you to get back.'
"I think within those three months, the manager proved his greatness to me.
"When I'm in management now, and when people say, 'What did you learn the most?' I tell them stories like I've just told you about what happened to me with my virus."