What was originally reported as a one month injury has been changed to an ACL tear according to Arsenal.com meaning Theo Walcott will miss the rest of the 2013-14 season.
Theo Walcott and Arsenal face more uncertainty at the forward position after Walcott went down with a knee issue in Arsenal's 2-0 win over rivals Tottenham at the Emirates.
Arsenal fell behind in the opening minute of the second half, but the Gunners would score three unanswered goals, two by Theo Walcott, to overtake West Ham United 1-3.
Making his first start since a long injury spell, Theo Walcott quickly thrust himself back into the fantasy picture by scoring twice, but Arsenal ran up against a buzzsaw in Manchester City and were thoroughly beaten 6-3.
Theo Walcott continued to be eased back into the Arsenal starting line-up with a substitute appearance against Marseille on Tuesday.
After a long spell out with an injury, Theo Walcott returns to the Arsenal squad against his former club Southampton in Week 12.
Theo Walcott is back in full training and could be in line to face his old club, Southampton.
Theo Walcott missed training yesterday, despite rumours that he would be fit for Arsenal's Champions League match against Dortmund, or possibly Manchester United this weekend.
Theo Walcott, recovering from groin and stomach surgery has suffered a setback in his recovery and will miss Week 9 against Crystal Palace.
Theo Walcott's abdominal injury has been diagnosed and the next step is minor surgery in Germany and missing four matches in all competitions.
Theo Walcott was a late scratch from Arsenal's win over Stoke with an ill-defined abdominal injury.
After a weekend that saw Walcott miss a couple of solid chances he cashed in with Arsenal's first Champions League group stage goal on the way to an Arsenal win.
According to Arsenal's official Twitter feed, Theo Walcott along with Jack Wilshere have been deemed "fully fit" for Arsenal's trip to Sunderland.
In England's World Cup qualifier against the Ukraine, Theo Walcott was treated by medical staff after suffering a "nasty" tackle in the 62nd minute.