West Brom coach Tony Pulis revealed a knee injury kept Ben Foster out of Monday night's 1-1 draw at Leicester.
Albion have yet to determine the extent of the injury, which the 34-year-old goalkeeper sustained during the international break while playing in the garden with his children.
However, Pulis admitted he is worried about the problem given Foster missed 10 months in the 2015-16 season with anterior cruciate ligament damage.
To compound his goalkeeping problems, stand-in Boaz Myhill, making his first Premier League start since April 2016 in Foster's absence, also finished the match at the King Power Stadium with an injury.