Arsenal forward Alexis Sanchez will miss at least two weeks with an abdominal strain picked up before last weekend's Community Shield victory over Chelsea.
Sanchez returned late to pre-season training with the Gunners due to his commitments at the Confederations Cup with Chile and will now have his start to the new Premier League campaign delayed.
He will certainly miss Friday's opener at home to Leicester City while Wenger confirmed he is also likely to sit out the trip to Stoke City a week later.
Wenger told a news conference: "He had a little abdominal strain that he caught on Sunday morning in training before he came to Wembley. He had a scan two days ago and he's out for a while I don't know is it two weeks or one more week but he will not be available.
"I think he will not play at Stoke.
"For us, Alexis Sanchez is a loss of course but we had all the other players prepared in pre-season already and it can happen in preparation any way. I don't think I would have included him certainly on Friday night - I don't think I would have started him."
Sanchez's Arsenal future has been subject of intense speculation throughout the off-season with Bayern Munich and Paris Saint-Germain backing out of a chase for the Chilean, who reportedly still interests Manchester City.
But Wenger says his striker remains concentrated on matters at the Emirates Stadium.
Asked to sum up Sanchez's state, Wenger replied: "Focused. Of course when you have treatment on medical bench it's not easy."