Arsenal defender Andre Santos has confirmed that a twisted ankle suffered in the Gunners\' 3-1 loss to Olympiakos will keep him sidelined for three weeks.The Brazilian\'s injury in Tuesday night\'s Champions League tie adds to manager Arsene Wenger\'s selection problems at full-back, with Kieran Gibbs, Bacary Sagna, Carl Jenkinson also unavailable.\"I twisted my ankle in a silly move,\" Santos told the Daily Express.\"The doctor thinks I\'ll be out for three weeks.\"Thomas Vermaelen could be in line to take over Santos\' duties at left-back for Arsenal\'s upcoming fixtures.