Arsenal manager Arsene Wenger has revealed that Theo Walcott's stomach problem flared up again in training last week, giving him no chance of playing in their next three matches.
Walcott has been out since mid-September after having minor surgery to repair a stomach muscle, leaving him unable to feature in England's recent World Cup qualifiers.
Wenger has admitted that Walcott's return to full training had to be scaled back after the winger complained of discomfort during sprints, meaning that his recovery will take at least two more weeks.
He told The Mirror: "He had a setback. He had to stop, to jog again, I don't think we will see him against Borussia Dortmund, nor Crystal Palace nor Chelsea. He is at least two weeks away now."
The 24-year-old's absence has not affected Arsenal's fine start to the campaign, which continued last weekend as the Gunners stayed top with a 4-1 win over Norwich City.