The France international has been out since undergoing a liver transplant in April, having also undergone treatment for a tumour last year.
He recovered from that original illness just before the end of the 2010-11 season and had recovered sufficiently to lift the UEFA Champions League Trophy that May.
This latest setback has sidelined the 32-year-old since February but Abidal is now targeting a December comeback.
He told the club’s official website: “I have started working in the gym and I feel fine. I will keep progressing and see if I can play before December.
“I’m better than three months ago. I am following the guidelines that the doctors have given me and the truth is I feel fine.
“I travel and enjoy being around the team and that environment.”
Barca have signed Spain international Jordi Alba to operate in Abidal’s usual left-back position, but the Frenchman’s versatility and experience could yet prove an asset to the Catalan club.