Simon has just undergone wrist surgery.
He said, "My wrist is fine, I don't have any pain and I need to keep it immobilised until the doctor says otherwise.
"Honestly, I was told that it would be immobilised for a long time. How long will depend on the rehabilitation process and how my wrist progresses when I take off the cast.
"I've gone through periods with a lot of pain, but whoever spends a whole season playing and has no pain, let them cast the first stone. It's normal, we live with it and whenever I've had pain that's prevented me from playing we've always resorted to injections. That's how it's been during the season and also at the European Championship."
Julen Agirrezabala is also out injured, but Simon is confident their fellow keepers are capable of stepping up.
He also stated: "Alex Padilla, with what I have been able to see in pre-season, I think he's doing very well. With what we have already seen of him when he was training with us and how he competed with Bilbao Athletic, he has the qualities to be a goalkeeper in senior football.
"Like everything in life, you have to prove it on the pitch and these days will be great for him to gain confidence, just like Oier (Gastesi). I think they are two goalkeepers who have quality and ability."