Dyer is gearing up to face the Irons for the first time since making the switch across the capital in the London derby on tonight.
He told the Fulham Chronicle: “It was the most frustrating time of my career. We got relegated and I only played a handful of games.
“I believe that if I got a run of games under my belt and stayed injury-free then I could've helped our cause more.
“It wasn't for a lack of effort. I tried everything physically possible to get on the pitch but it wasn't to be.
“I'm absolutely gutted because it was four years where I never played three games on the trot. If you considered what I went through on a personal level I look back at that with a lot of regrets because it was a case of what if?
“It's a fantastic club with fantastic fans, but I was never on the pitch enough to justify the wages and the fee they paid for me which is very unfortunate.”