The Barca captain was forced off in the 36th minute following a late challenge from Sevilla defender Mariano, barely 10 minutes after Jeremy Mathieu was substituted with a hamstring problem.
Barca said in a statement on Monday that Iniesta would be out for at least two weeks, missing Wednesday's Super Cup second leg plus the first two La Liga games of the season at home to Real Betis on Saturday and at Athletic Bilbao the following weekend.
Mathieu is set for three weeks on the sidelines.
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New signing Lucas Digne, who made his debut when he replaced Mathieu on Sunday, could be line for a first competitive start on Wednesday after joining from Paris St Germain.
Denis Suarez is a possible stand-in for Iniesta in the second leg with Sevilla although coach Luis Enrique may also choose to opt for new signing Andre Gomes or Rafinha who missed most of last season with a serious knee injury.
(Editing by Tony Jimenez)
