Abidal diagnosed with liver tumour
The 31-year-old France international will be operated on at a clinic in the Catalan capital on Friday, the club said on their website.
They gave no further details and asked that the player's privacy be respected.
It was unclear how long Abidal would be out of action. His absence for any length of time would be a severe blow to the La Liga leaders given his superb form this season and their relatively limited squad.
The athletic Abidal normally plays at left-back but has filled in brilliantly in central defence when regulars Carles Puyol and Gerard Pique have been absent this season.