"I feel very happy and proud to be at this club and I will return my experience and knowledge as best as I can," he told the club's official website.
"I have been a professional for a very long time now and I won more than 50 caps for Switzerland. I think I have a lot to give.
"Of course you want to be first-choice, but as I have said I am behind a wonderful goalkeeper. It has been a new experience for me, but one that I have still enjoyed.
"I'm already looking forward to the start of the new season, because last year was a massive achievement for everyone involved.
"It is going to be difficult to improve, but the challenge itself presents a wonderful opportunity."