The Spain international went down heavily after winning an aerial challenge with Diego Costa in the 10th minute of the Champions League quarter-final, first-leg clash at Camp Nou and was replaced by Marc Bartra.
Barca confirmed after the 1-1 stalemate at the Camp Nou that Pique would miss up to a month, ruling him out of the return against Atletico, the Copa del Rey final against Real Madrid and at least three La Liga matches.
A club statement read: “After only 10 minutes of play Gerard Pique suffered a bad fall.
“The player asked to be subbed off after he noticed pain in his hip due a pelvic contusion.
“The medical team advise he will be out for four weeks.”
The news comes as a major blow for Tata Martino’s men, who have been without Pique’s regular central defensive partner Carles Puyol for much of the season through injury.
Bartra deputised well against Atletico and the 23-year-old will have to maintain that level of performance alongside midfielder-cum-defender Javier Mascherano over a crucial period of the season.