Since signing for Arsenal in 2009, Thomas Vermaelen has been a key figure in the defensive line for Arsenal. The Belgian brought steel to what was often a very light back four for Arsenal, harking back to the days of Adams, Bould, Winterburn, Keown et al. Recently, however, this is not been the case. Inconsistent performances from the now club captain have often given Wojciech Szczsny extra work to do between the sticks yet presumably due to his captaincy duties, Vermaelen retains his position in the team. The partnership of Koscielny and Mertesacker has flourished during Vermaelen's time out of the starting XI but is rarely started. Wednesday's performance against Bayern Munich is testament to the understanding between the French and German internationals amongst many other performances. In fact the constant in the centre back pairing is often the towering Per Mertesacker and many agree that Koscielny seems to get even more out of Mertesacker. If this partnership is broken to make way for Vermaelen on Saturday, Swansea's front line of Michu, Routledge, Dyer and Hernandez will no doubt look to hound the Belgian in to dropping another clanger.