LONDON -- Arsenal signed Kim Kallstrom on loan from Spartak Moscow on Friday even though the Premier League club identified that the Sweden midfielder was carrying a back injury during his medical examination.
It is unclear how long Kallstrom, who was brought in to alleviate the team's midfield problems, will be sidelined.
Arsenal's communications director, Mark Gonnella, says the club decided to proceed with Kallstrom's signing despite the injury.
Jack Wilshere and Aaron Ramsey are currently out injured while Mathieu Flamini will miss the next three games because of suspension.
Arsenal, which hosts Crystal Palace on Sunday, is second in the table -- a point behind Manchester City.