Sonko on trial with Royals
Former Reading defender has been drafted in on trial for the club, in an attempt to solve their ever growing centre back problem.
Sonko left the Royals in 2008 for Stoke, in a deal to be worth around £2.5 but he failed to make an impact at the club, only making 14 first team appearances and was released last month.
The Senegalese international then had loan spells at Championship rivals Hull and most recently Portsmouth.
The 30-year old defender is loved by many at the club and earned the nickname of 'Superman' for his heroic-like performances in a Reading shirt.
Sonko is currently training with the Reading squad and will play some part in the Northampton friendly tomorrow afternoon.
McDermott told the RFC official site: 'I've spoken to Ibrahima and he's very keen to train with us so we will see where it leads us.'
The Royals boss also revealed a second deal for a defender could be close, but refused to name the mystery player.