Foster has not played since the end of August because of a broken toe, and the England international has admitted that he has found it tough on his return to training after over three months out.
The 30-year-old told the Express & Star: "In the next week or two, I should be fairly good to go again. It's going to be quite intensive training.
"It will take a while to get my eye back in again and get my body used to diving about again. I've only been diving around for a couple of days and my body is killing. There is only so much that you can do in the gym to keep yourself fit.
"But the tiredness that you get from diving around and your muscles taking beatings every day, it's different – I've been going home and sleeping."
Foster has made 72 appearances for the Baggies since making his debut in 2011.