Liverpool defender Daniel Agger has admitted he is concerned about his niggling back problems.
Agger is doubtful for this weekend's Merseyside derby after picking up an injury on international duty with Denmark in midweek.
The 25-year-old admits his career could have been finished if he had not received treatment on the back problem and he is worried that the injury could return.
"The last few weeks, I have got new treatment for my back injury and if I had not got it, it could have threatened my career," Agger told Sporten.dk.
"It has been in my thoughts. In case it was not sorted now, my situation would be unbearable for 10 years.
"Right now, it looks like the treatment is working, but in the back of my head I thought it might get worse again."