Per Mertesacker out for a month

Per Mertesacker will reportedly miss a month of action after suffering an ankle injury.

The Arsenal defender picked up the injury during the Gunners' 2-1 victory over Sunderland on Saturday and will now miss games against AC Milan, Sunderland and Tottenham Hotspur, according to The Sun.

The centre-half flew to Germany last night for scans and to meet the German national team doctor.

The 27-year-old's injury has opened the door for Thomas Vermaelen to return to central defence after covering at left-back in recent games.