The South Africa international revealed he turned down a new contract at Rovers to move to Fratton Park.
"I don't have any regrets joining Blackburn and leaving Blackburn," he told the Lancashire Telegraph. "I had fantastic years at Blackburn. I played twice in the FA Cup semi-finals and played UEFA at Blackburn, but I thought it was time to move on.
"Luckily, Portsmouth came along - they were one of the teams interested. And it wasn't a difficult decision for me to make.
"Sam is an experienced manager and we got along very well "He wanted to offer me a new contract as my contract was running out.
"But I thought it was time for me to move on, but he was a great manager. He's been in the game for years. He's got experience in this league, so I have got a great respect for him."