The 45 year old American, whose surprise Major victory came at Royal Troon in 2004, recently lost his US PGA Tour card but still has a European Tour exemption courtesy of his Open win.
Having dropped to 545th in the Official World Golf Ranking, Hamilton showed signs of a return to form by playing his first 15 holes in three under par.
That took him into second place on seven under after his opening 66, one behind overnight leader Nicolas Colsaerts.
The big-hitting Belgian was amongst the day's later starters, but another Major winner was also closing in.
Martin Kaymer's return to action following his US PGA Championship triumph saw the German card three birdies through his first 12 holes and move to six under, alongside Shiv Kapur, Kenneth Ferrie and home favourite Joost Luiten.
|T4||LARA, José Manuel||ESP||18||-9|