Former world number four Robin Soderling has retired from tennis after suffering glandular fever since 2011.
The 31-year-old Swede, who became the first man to beat Rafael Nadal at the French Open in 2009, has not recovered sufficiently to return to the sport.
Soderling reached the French Open finals of 2009 and 2010.
"I've realised that I will not be healthy enough to be able to play tennis at the level I demand of myself," Soderling told tennis.se.
"For that reason I have decided to end my career as a professional tennis player."
The Swede, who also reached the quarter-finals at Wimbledon and the US Open, had hoped to return to competitive action but has finally admitted defeat.
"A few weeks before the Swedish Open in Bastad in 2011 I became ill with glandular fever," added Soderling.
"Since I was not aware of the seriousness of this, I made the mistake of continuing to train and compete with the virus in my body, which resulted in a sharp overtraining syndrome. I have since struggled to recover completely from this.
"With the disease it has been impossible for me to train 100% and I was forced to rest after any physical effort. In some periods I felt so bad that I was completely bed-ridden.
"This past year, however, my health improved and I have been able to increase my exercise levels, but my recovery after exercise is unfortunately still not as I would like."
Soderling played his final match in July, 2011, beating Spain's David Ferrer to win the Swedish Open in Bastad.