Barcelona defenders Gabi Milito and Martin Montoya are facing six weeks on the sidelines with injuries picked up in the 2-1 defeat at Real Sociedad.
Argentina international Milito, 30, was replaced with 13 minutes remaining due to a torn calf muscle, while 20-year-old B team regular Montoya sustained a broken collarbone just 12 minutes into his full debut.
A statement on Barcelona's official website read: "Tests carried out this morning have confirmed that Gabi Milito has a tear in his calf muscle and will be out for six weeks, whilst Montoya will be operated on this Monday and will be out for six weeks.
"The B team defender, who made his first-team debut at Anoeta, suffered a broken collarbone and he will have an operation on Monday. He is expected to be out for six weeks.
"The injuries to Milito and Montoya leave Pep Guardiola with a further headache at the back, where Maxwell, Adriano and [Eric] Abidal are already out and a total of four first-team squad defenders are injured.''
Barca require four points from their remaining four games to retain the league title, and face Real Madrid in the second leg of their Champions League quarter-final at the Nou Camp on Tuesday.