Barcelona fear that boss Pep Guardiola could miss next week's crunch Champions League clash with Arsenal.
The 40-year-old has been suffering severe back pain and was taken to hospital after last night's 1-0 league victory at Valencia that left the Catalans 10 points at the top of the table.
Despite deciding to attend the match with acute discomfort in his lower back, there are now doubts over whether he will be able to make it to the touchline for the second leg with the Gunners.
Agony: Barca coach Pep Guardiola can barely stand because of the back pain not even eased by Lionel Messi scoring the only goal to beat Valencia
Guardiola’s No 2 Tito Vilanova said: ‘Pep is not feeling great and he got through the match as best he could. He is having a bad time of it and he doesn’t even know where to put himself.’
Guardiola has been diagnosed as suffering from a herniated disc.
A Barca statement read: 'Early this morning, Guardiola was admitted to hospital in Barcelona to continue treatment and study of his acute back pain.
'His medical examination has revealed that he has a herniated disc, and he will be treated with drugs and epidural injections. His release from hospital depends on the progress he makes.'
Guardiola had to cancel a press conference on Tuesday because of his back problems.
Barcelona face struggling Real Zaragoza at home on Saturday before meeting Arsenal three days later looking to overturn a 2-1 first leg defeat and knock the Londoners out of the tournament for the second successive year.