The Republic of Ireland international has been struggling with a niggling back problem but came off the bench to net from the penalty spot in Saturday's 2-1 defeat against Norwich.
Long is hopeful of playing a full part in this weekend's trip to Stoke and is confident he will soon be "as good as new".
He told the club's official website: "I've been in a bit of pain with my back and the medical staff tried to manage it all last week.
"The medical staff know what they are doing and getting me out on the pitch at the moment is a hard job. I'm trying to play through the pain and hopefully I will come out the right side of it in a couple of weeks.
"The problem is always there. It's constant. But it's one of those things you can play through. I'm just doing the best I can to make myself available for selection on Saturdays. But I'm pretty confident that in a couple of weeks I'll be back to being as good as new."