The Spanish defender is likely to be out for six months and the manager is considering a replacement.
Barcelona boss Ronald Koeman will be looking to sign a defender in January following the injury of Gerard Piqué and possible surgery.
Piqué suffered an injury during Barcelona's 1-0 defeat to Atletico on Saturday and was forced to leave the pitch in the second half. Rumor has it that the former Spain defender will likely be sidelined for six months, thus missing the season.
Dr. Ramon Cugat, an orthopedic surgeon who recently operated on Anso Fati, will meet with Piqué on Wednesday, and the final decision will be made that day.
Cugat told Mundo Deportivo:" It is a lot to discuss how long he will be out because every knee is differentWe must be prudent, discuss it with the player and then decide. We still don't know which treatment we will use, whether surgical or not. The objective is to make the knee as stable as possible.In addition to the cruciate injury, he has injured the internal lateral ligament.
"That can be cured with biological therapies. In this case there is no fluid on the knee, which plays in favour of possible conservative treatment, rather than surgery."
Piqué has made ten appearances for Barça this season and has been a critical member of the team since returning to the Nou Camp in 2008. In all three games that Piqué has missed this season, Barça has failed to win, conceding an average of two goals.
Now Koeman also talked about the possibility of buying a defender in the winter transfer window: "We know that it is an important loss for us, and possibly for some time. We are looking and have previously looked.
"One of those positions we are looking at is that central issue. But today we cannot do anything. If there is any possibility we can then I will have to talk to the club.
"He has been here for many years, he has a huge personality and it is a significant loss. It is sad for the team and for the club. It is difficult, but we have to accept and see how we solve this issue."