Arsenal get surprise injury boost for Chelsea derby as Mikel Arteta issues three-man update

The Gunners face their toughest test of the season so far as they take on Xabi Alonso’s side, who have also won both of their opening two matches.Timber is yet to feature this season after undergoing minor surgery over the summer, and was not expected to return until later in September.However, the Dutchmanhas stepped up his training and will be assessed against of kick-off."He's in really good condition at the moment,” Arteta said of Timber. “He's been training with us now, he's in a good place."Asked if Timber could face Chelsea on Sunday, Arteta said: "We will decide again tomorrow after training." Bruno GuimaraesGettyBruno Guimaraes is expected to be fit, despite not being seen in first-team training on Thursday.His workload continues to be managed but Arteta confirmed at his pre-match