The 27-year-old struggled to make an impact for the club last season – making just six appearances – but he has vowed to challenge this time around.
"It can change very quickly. From my own experiences I know that, so I am ready to step up. I feel confident that I am able to be number one," he told the club's official website.
"I am very happy, I must say. I had a little problem with my shoulder, but so far everything has been going really well for me. I am happy with my fitness levels and the way I feel on the pitch.
"Pre-season is always a fresh start, and it is hard work for us. We have to do all of the running and gym work too, it's not like we just have to do just goalkeeping! It has been good work over the past few weeks."
Arsenal open their Premier League campaign against Sunderland on Saturday.