The 24-year-old joined the south coast club from Preston North End for £6 million in 2007, but made just 33 league appearances - netting three times - in a frustrating spell under, first, Harry Redknapp, Tony Adams and Paul Hart.
The England international, who has one cap and one goal against Andorra in March 2007, has now joined Owen Coyle's side on loan until January.
And he expressed his delight at finally being able to get away from Portsmouth and attempt to reignite his career with the Clarets.
"It's a relief to get out of Portsmouth," he said in the Daily Star.
"Harry's a good man-manager but it just didn't seem to work with me. After a few weeks he didn't fancy me as a player.
"I was down there on my own with no family but I just had to get on with it. It was horrible. I lost so much confidence.
"I was so down, I didn't want to go to training sometimes. I was just on my own, sitting in the apartment, watching TV, playing computer games, going to bed at stupid hours of the morning.
"That's been the lowest point of my career and hopefully this will be a new slate."
