Walcott has been out of action since rupturing his anterior cruciate ligament in a 2-0 FA Cup win over north London rivals Tottenham back in January.
The England international was back in training earlier this month and was thought to be in contention for this Saturday's visit to the Stadium of Light to take on Sunderland.
That game will come too soon for the 25-year-old, but Walcott is expected to be ready in time to face Burnley at the Emirates Stadium next weekend.
"He has to get used to contact again. It takes time to get used to being kicked again," Arsenal manager Arsene Wenger said of Walcott in his pre-match press conference on Friday.
"After seeing what he has gone through over the last nine months, you respect him more."
There is less positive news on defender Laurent Koscielny, though, with the France defender set to remain on the sidelines until after next month's international break due to an Achilles problem.
"I cannot give you any date," Wenger added. "I hope he [Koscielny] will be available after the next international break."
Arsenal travel to Sunderland on a run of one win in their last seven Premier League games, although they did produce a stirring comeback in the UEFA Champions League in midweek to beat Anderlecht 2-1.
Sunderland are 17th and head into the contest on the back of a humiliating 8-0 thrashing at the hands of Southampton last weekend.
But Wenger is wary of a defensive backlash from Gus Poyet's side in the wake of that result.
He said: "The danger is that they [Sunderland] now focus very hard on defending and that we get very few openings."
