Manchester United midfielder Darren Fletcher is to take an extended break from football due to health reasons, the club confirmed on Tuesday.
The Premier League champions said Fletcher, 27, had been battling the bowel condition ulcerative colitis, which had already forced the midfielder to miss several months last season.
United said the club had previously attributed Fletcher's absence to a mystery viral illness in order to protect the player's medical confidentiality.
"Darren has, in fact, been suffering from ulcerative colitis (a chronic inflammatory bowel condition) for some time preceding this," United said.
"Whilst he was able to maintain remission of symptoms for a considerable period this has proved more difficult recently and Darren's continued desire to play and his loyalty to both his club and country has probably compromised the chances of optimising his own health and fitness.
"He has therefore accepted medical advice to take an extended break from the demands of training and playing in order to afford the best chance possible of achieving full remission once again.
"We request that his privacy is respected and hope that the removal of the additional stress associated with speculation regarding his health will also aid his recovery."
Fletcher's absence is another blow to United's season, which suffered a huge setback last week when the club were eliminated from the Champions League in the group stage for only the third time in 16 years.
The Scotland international's illness leaves manager Sir Alex Ferguson with yet another headache in the champions' problem area of midfield.
Scotland manager Craig Levein meanwhile wished Fletcher a speedy recovery.
"I am obviously absolutely devastated for Darren because I know how hard he has worked to get back to playing regularly for his club and country," Levein said.
"He is one of the most inspirational players I have had the pleasure of working with and on behalf of his Scotland team-mates and my backroom staff I sincerely hope this time off, allied to the support of his family, will enable him to make a full recovery.
"I spoke with Sir Alex Ferguson and Darren this week and the most important thing at this stage is for the player to be given time to rest and recuperate.
"Nobody is more committed to his country's cause than our captain."