The Baggies' No.1 is a doubt for Saturday's trip to Wigan after visiting a German doctor over his persistent complaint, which flared up during the win over Southampton on Monday
The 29-year-old missed the final match of last season after picking up the injury, and was also forced to miss part of pre-season.
The former England international aggravated the problem again in Monday's win over Southampton, leaving manager Steve Clarke sweating over his fitness for Saturday's trip to Wigan.
Clarke told reporters: "Ben is in Germany. Most of you noticed on Monday night 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."
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"We've got good back-up keepers here. Myhill played on loan in the Championship last season [at Birmingham] and had a really good season," Clarke continued.
"He trains well every day and, if I have to rely on Boaz to play, I would be happy with that."