Barcelona will be without Mali international Seydou Keita for up to a month with a hamstring strain.
The 30-year-old was forced out of Barca's 2-1 defeat to Atletico Madrid early on and replaced by Pedro on Sunday evening.
Initial tests show Keita will miss up to four weeks of action, although he will undergo further tests on Tuesday.
The former Sevilla midfielder could miss four Liga matches for Barca along with the first leg of their UEFA Champions League clash with Stuttgart.
The injury to Keita is the last thing manager Pep Guardiola needs with the likes of Dani Alves, Yaya Toure, Dmytro Chygrynskiy and Eric Abidal already on the sidelines.