Feb 1 (Reuters) - Arsenal midfielder Kim Kallstrom faces a lenthy spell on the sidelines after picking up a back injury a day after completing his loan move to the Premier League club, Britiah media reported on Saturday.
The BBC reported Kallstrom is being assessed by medical staff after suffering the injury in his first training session with the club.
Arsenal signed the 31-year-old Sweden international on loan from Spartak Moscow until the end of the season to bolster their depleted midfield which is already missing Aaron Ramsey, Jack Wilshere and Mathieu Flamini.
Ramsey is out for up to six weeks with a thigh problem, Wilshere has an ankle strain and Flamini is serving a four-match ban.
Arsenal, second in the Premier League, host Crystal Palace on Sunday. (Reporting By Sam Holden, editing by Pritha Sarkar)