7. Thomas Vermaelen
Arsenal captain Thomas Vermaelen was a roaring success almost instantly after moving to the Emirates from Ajax in 2009, but that mix of pace, power and presence now looks a distant memory for the Belgian international.
Vermaelen's chances of becoming a Premier League great have been ruined by consistent long-term injury problems and the terrific partnership struck by Arsenal colleagues Per Mertesacker and Laurent Koscielny at the heart of defence.
The 28-year-old has featured occasionally and looked fairly reliable, but just doesn't appear to have the same burst of acceleration or spring to meet aerial threats that made him stand out during his first season with Arsenal.