"It's getting there, I'm feeling much better and hopefully I'll be training in the next week or so," Etherington told the club's official website.
"It's hard because there are no reserve games until early January but hopefully I'll be back by then. It's just been a case of resting it.
"I got a couple of whacks up at Burnley and I tried perhaps to come back too early. I went over on it again in training and I just felt I wanted to get it right. I wanted it to settle down and get it right."