Barcelona forward Neymar has been ruled out for up to a month due to a left foot injury.
And he will be joined on the sidelines by defender Jordi Alba, who has injured his hamstring.
The duo picked up the injuries during Wednesday night's 2-1 Copa Del Rey final defeat to Real Madrid, a loss which capped a very bad few days for Barca.
The Catalan side were knocked out of the UEFA Champions League at the quarter-final stage by Atletico Madrid last week and their La Liga title hopes were dealt a huge blow when they suffered a shock 1-0 defeat at Granada last weekend.
Brazilian international Neymar and Spaniard Alba will miss the majority of Barcelona's remaining La Liga matches, although it is possible they could return for the final game of the season, at home to Atletico on 18 May.
A Barca statement read: "Neymar sustained a contusion with caused an edema (a swelling) in the fourth metatarsal in his left foot.
"He will be sidelined for four weeks."
And Alba will be out for three to four weeks with a torn muscle in his right hamstring.
The news will be a concern for the respective national teams, with hosts Brazil kicking off the World Cup against Croatia on 12 June before defending champions Spain begin their campaign against Holland the following day.