The 25-year-old, who suffered the injury against Tottenham Hotspur in January, was rumoured to be set for a return in the North London derby on September 27, but he has insisted that the game is not a realistic target.
"I'm all about positive thinking," Walcott told The Mirror. "When you think about injuries, you don't want to be all negative about it. If you're negative or down in the dumps, then it'd take longer.
"This injury was always going to take nine months. I haven't put a specific date or looked at a game yet.
"I think there was rumours of me coming back for the Spurs game, which is definitely not going to happen, that's for sure, but I'll definitely be there for the one in February."
Arsene Wenger has not yet revealed when he will consider Walcott for selection.