Barcelona look set to be without midfielder Cesc Fabregas for three weeks after he suffered up a leg injury.
The former Arsenal star picked up a muscle problem in his right thigh during training on Saturday, the La Liga club said.
Iniesta, who has been out with a torn leg muscle, trained with the Champions League holders on Friday but is unlikely to return for Sunday's league game with Sporting Gijon.
Chile international Sanchez is recovering from the same problem.
Fabregas has been a revelation since signing from the Gunners in August, helping the club win the Spanish Supercup on his debut.
The 24-year-old has made seven appearances for Barca, scoring four goals.