Arsenal manager Arsene Wenger has been handed a defensive conundrum ahead of this weekend's Premier League opener against Crystal Palace. The Gunner's impressive 3-0 dismissal of English champions Manchester City in last Sunday's Community Shield final was undermined by injury to Laurent Koscielny, leaving Wenger with a shortage of options at centre-back. Koscielny is expected to miss the clash with Palace with an achilles problem meaning Per Mertesacker is the only remaining senior centre-half for Wenger to select from. Koscielny's injury came on the same day club captain Thomas Vermaelen joined Barcelona for £15 million and combined, these issues could put the Gunners bang in the market for a new centre-back before the transfer window slams shut in under three weeks. As it stands, only rookie new signing Calum Chambers forms a credible option to partner Mertesacker at the heart of the defence and Wenger may opt to examine the market for someone with more seniority to the 19-year-old former Southampton defender as he looks to ease his mini-crisis at Emirates Stadium. With the new season set to start in four days' time and with only a few more weeks left to run of this summer's transfer window, we take a look at 10 Dream Replacements For Thomas Vermaelen to solve Wenger's woes at the back. Click 'next' to get started.