The experienced No.1 damaged his hamstring during yesterday’s 2-0 win over Watford at the Emirates.
Taking a goal kick at the end of the first half, Cech pulled up and was replaced by summer signing Leno.
The Germany international has expressed his desire to get more game time, especially in the Premier League.
Leno’s only start to date came in the Europa League, but he is now set for a run in the side with Cech sidelined.
The 36-year-old is likely to be out for a few weeks given the injury.
As a result, Leno will play the next two games at least before the international break.
Arsenal go to Qarabag in Azerbaijan on Thursday before travelling across London to face Fulham in the Premier League next Sunday.
Speaking on Leno after yesterday’s win over Watford, Emery said: “He is working very well with the goalkeeping coaches.
“I think Bernd Leno can learn from training with Petr Cech every day”
“I’ve spoken with him. What’s most important is that when the team needs him, he helps us.
“He’s prepared and he did that well against Vorskla, on Wednesday and today.
“It’s the same with Emi Martinez. We have three very good goalkeepers.
“Petr Cech’s performances and experience are very important for us. I think Bernd Leno can learn from training with Petr Cech every day.”
Asked whether Leno can stay in the team when Cech returns, he added: “He can convince me, but not now.
“I am very convinced with him! He played because of an injury to Petr Cech but I am very happy with him.
“He has waited for his moment. It’s arriving and the performance is the best for him and for us.”