Gunners boss Arsene Wenger has confirmed the Chilean star won't play in the season opener at the Emirates.
Sanchez missed the Community Shield win over Chelsea on Sunday after returning to training late after a busy summer with his country at the Confederations Cup.
And Arsenal will have to do without him again when they get their Premier League season underway against the Foxes on Friday.
“Sanchez will not be available," Wenger said.
"He had a little abdominal strain that he caught on Sunday morning in training.
"He had the scan two days ago. He’s out for a while.
“He is focused. When you have treatment on the medical bench it’s not easy.”
Wenger was quizzed about interest from Paris St-Germain in Sanchez.
When asked if the French club had been in contact over a deal, he said: "No".
He was then pressed on interest from other clubs, and added: "I cannot tell you that.
"We are not open to any offers anyway.”
Wenger also discussed his team selection for the clash with the Foxes.
"I have plenty of uncertainties about the players who didn’t play against Chelsea," he said.
"Will they be available or not? For example Ramsey, Ozil, Mertesacker, of course Koscielny is suspended.
"I have players coming back who have not played, like Mustafi.
"Alexis will not be available for example, so I cannot go into the game with too many uncertainties.
"I can take a gamble on one, maybe maximum two, but I focus more on the players who had the right number of competitive minutes in recent weeks.
"We play quality opponents - Leicester have a good way to stop people because they defend very well, they are dangerous on counter-attacks, so we have to put a decent pace into the game to be dangerous."
