This means Barca will be without their dependable star for the trip to the Bernabeu on on Saturday, December 23.
Barcelona have now confirmed Umtiti will miss the next eight weeks - missing the final games of 2017 against Villarreal, Deportivo La Coruna and arch-rivals Real in the final match before the winter break.
The club captain was replaced after 53 minutes against Celta with the club now confirming he will miss the visit of the Portuguese giants due to "muscle fatigue in his left calf".
And there were further causes for complaint here as Luis Suarez had a legitimate goal disallowed for offside.
Sprinting to keep up with former Liverpool forward Iago Aspas, the France international was forced to pull up, allowing the Celta forward to race through unchallenged and tee up Maxi Gomez to level the contest at 2-2. He was denied by Marc-Andre ter Stegen, only for Aspas to volley home the rebound. "The injury cost us the goal, it was an accumulation of catastrophes, conceding the equaliser and the injury".
A subdued Barca were temporarily brought back to life when Denis Suarez was introduced from the bench to provide some midfield creativity, with a fine passing move culminating in the hosts' second. Find out by following our live matchcast.
Who will come out on top in the battle of the managers Ernesto Valverde or Juan Carlos Unzué?