Neither player participated in training on Monday casting further doubt on their availability. Turan reportedly underwent therapy on his injured groin, but there was no information concerning Diego Costa and his health.
Both players sat out of Atléti's win over Villarreal on Saturday and their attack clearly missed them.
Costa is recovering from a thigh injury suffered against Barcelona in the first leg and is considered the less likely of the two players to be ready on Wednesday. Turan's hernia injury is considered less serious and has the better chance of being ready to play.
On the positive side for Atléti, they'll get Raúl Garcia back from suspension and midfielder Gabi will be rested after sitting out on their league match over the weekend because of suspension.
Barcelona and Atléti are tied 1-1 after the first leg at the Camp Nou last Tuesday.