Duff said: "Everything was going great until December 21 but I've just had a couple of injuries so hopefully I'll be back soon."
"I'm desperate to get back but I love it at Chelsea. It's been the best decision that I've made in my life.
"At Fulham, I remember getting the ball and going past one or two players and then having a shot. It would all have been worth it if the ball had gone in!
"But it didn't and I knew straightaway that I'd done something. I was back playing again in about three weeks, which was good, but then I did my Achilles.
"I don't know if it was related to my shoulder or the way I was running or whatever, but it's been a depressing six weeks, to be fair. I'm just desperate to get back."
Unfortunately, it looks likely that Duff won't even have a place on the bench for tonight's game with Pompey...