Hernandez said: "I have talked with him. Carlos has the chance to return to Arsenal in August. He only wants to play. He knows that the opportunity will come sooner or later as he has a contract with Arsenal.
"I haven't talk with the Gunners representative yet, buy I know that they want Carlos back as soon as possible."
Vela is said to be excited about the opportunity to return to north London.
Hernandez added: "This is something very important for him. Every player wants to be part of such a good side. Carlos is very excited about it, but we will have to wait until June to end the story."