The 29-year old has been struggling with a recurring problem which has at times forced him to kick on his non-preferred leg and the Baggies are keen to get to the bottom of the issue.
Albion boss Steve Clarke is hoping to get some good news from the trip and still believes the club can manage Foster's problem.
"Ben is in Germany," Clarke said. "Most of you noticed on Monday night (against Southampton) that he was kicking with his right foot and not his left foot.
"He has gone out to see a specialist. We are waiting on the diagnosis. Fingers crossed, it is positive and I'm hopeful he is available to play again at the weekend, kicking with his right foot.
"It is a problem with the groin and hopefully it is something we can manage in the same way as with Shane Long and his hamstring over the last few weeks.
"If we can manage him, then we can get a few more games out of him. What are his chances for Saturday? Probably 60-40 in his favour."