"He's only shown flashes of what he can do at Chelsea. But if he's playing regularly, I think he can light up the Premier League again because he's a quality player.
"And I'm not just saying that because he's my son. Technically, he's a very good footballer with a lot of drive and passion, and he works very hard for the team.
"I told him two years ago to leave Chelsea because I couldn't see the end of the rainbow for him.
"I could only see him getting sporadic starts and you can't do that at his age.
"Shaun is 26 now and being at a club like Portsmouth, where he's going to play regularly, will boost him."