Ronaldinho will miss Barcelona's opening game of the Primera Liga season at Celta Vigo on Monday because of an injury picked up during his side's 3-0 European Super Cup defeat by Sevilla on Friday.
The 26-year-old Brazilian World Player of the Year bruised his left thigh.
"Ronaldinho suffered a blow and he has to be given time to recover," Barca coach Frank Rijkaard told a news conference on Sunday.
The Spanish and European champions will also be without Dutch midfielder Mark van Bommel, who has agreed a move to German champions Bayern Munich.
"Van Bommel has got a winning mentality and he wanted to find a team where he would have more of a chance to play," said Rijkaard.