Both players have contracted swine flu.
The Spanish side confirmed the infection within their ranks that rules out the two stars for Tuesday's Champions League showdown.
"Abidal and Toure have viral-like symptoms with fever and general discomfort," read a statement on FCBarcelona.cat.
"Relevant tests have been carried out on both players and these have confirmed that it is swine flu.
"This Friday at midday the club's medical services informed that Abidal had swine flu and in the afternoon the tests carried out confirmed that Toure was also suffering from it.
"The medical services are working following the protocols established by the health department isolating the players, carrying out symptomatic treatment and giving appropriate hygienic measures."