5) Oleg Luzhny
The Ukrainian international was a consistent performer for Dynamo Kyiv before Arsenal decided to sign him in 1999 and while he made 108 appearances in all competitions for the Gunners, he was never fully trusted.
Luzhny was generally used as a backup for either Lee Dixon or one of the centre-backs and he never looked assured despite the faith shown in him by Arsene Wenger.
