Arsenal duo Robin van Persie and Laurent Koscielny have been ruled out of Wednesday's rescheduled fixture with Stoke at the Emirates.Striker Van Persie is out with a hamstring injury while French defender Koscielny is suffering from back soreness.Both injuries are minor and are not expected to rule either player out of Sunday's Carling Cup final against Birmingham City.But the loss of Van Persie is still worrying given the 27-year-old leads the Gunners' scoring this season.The in-form Dutchman has found the net five times in his last three appearances, including the equaliser in Arsenal's stunning 2-1 defeat of Champions League rivals Barcelona.Abou Diaby also has a calf complaint, but the French midfielder is already suspended following his red card at Newcastle United.Arsenal boss Arsene Wenger has outlined the importance of possession against the Potters, who will look to exploit their height up front from set pieces and the touchline, where Rory Delap will unleash more of his trademark long throws."What is important for us against Stoke is we (make sure) we have the ball," Wenger told Arsenal's official website. "The more we have the ball, the less they will be dangerous in the air. We will try to dominate the game; as long as we have the ball they cannot be dangerous."Arsenal trail Manchester United by four points in the Premier League standings, and Wenger is aware just how important Wednesday's fixture is."We know we are in a strong position in the Premier League," he said."The players know that at home our results will have a vital importance on our chances of winning the Premier League. The focus will be natural - this team wants to win every single game."