Aaron Lennon staked his claim while Walcott was sidelined, while David Beckham is a squad regular and Shaun Wright-Phillips seized his chance this week, scoring one and setting up another in the friendly against Egypt at Wembley.
"Without a doubt, there's a lot of competition," Walcott said. "We want all our players back 100% fit and I'm just finding my feet now with my fitness.
"Hopefully I can play consistently for Arsenal, stay fit -
that's the most important thing - and have a good end of the season.
"I feel as fit as anything now, I'm training well and just need to put the work from training into games now.
"It's sort of pre-season, I've had around seven games and that's normally what you have in pre-season. Its been up and down but I'm glad to be back fit now."
Walcott cannot remember the last time he watched footage of his hat-trick in Zagreb and he is determined to move on and put in other performances people will remember.
"For me, that's in the past, I'm trying to concentrate on every game, try and stay fit, that's the most important thing, give 110% in every single game," he said.
"It's all about the present. I'm trying to play well for Arsenal and go on from there.
"It does seem like a long time ago, with all the injuries I've had. It's been very frustrating so I've just put everything in my mind of trying to get back fit."
Walcott is hoping that coach Fabio Capello will have a real dilemma deciding who to take to South Africa.
He added: "It's fantastic competition to be among these world-class players - it's a headache for the manager and you'd have to ask him who is going to be in the squad on the day.
"It's healthy completion and you want to try and perform to try and start in every single game."
Arsenal v Burnley Last Goalscorer: Walcott, T. 13/2