The 25-year-old has been out of action since January when he suffered ligament damage against Tottenham Hotspur in the FA Cup.
While Walcott has refused to give a date for his comeback, the England international is pleased by how his rehabilitation is progressing.
"The knee is going really well. I am doing some good stuff with the physios and fitness coaches and we have worked really hard throughout the summer," he told Arsenal's official website.
"Things are looking really good and I have worked very hard for the last five months now.
"The most important thing is getting the strength back and it has pretty much nearly healed - it is just about building up that stability and strength again. It is coming along nicely and I am really pleased."
Arsenal start the new Premier League season at home to Crystal Palace on August 16.