However, the Baggies boss appears reluctant to wait until the end of the season to know whether Blues are willing to part company with Foster, who moved to the Hawthorns on a season long loan deal last summer.
"We need an answer because, at the moment, there a lot of talented keepers looking for clubs," Hodgson has said.
"We are in a position to attract people to the club, we can offer them Premier League football, good wages and a good football environment.
"What we've got to be careful of is not falling between two stools in waiting for Ben and hoping for Ben to join us. Suddenly when the day comes and we are told Ben is out of the question, suddenly all the other people we've been interested in are no longer available.
"Good quality keepers are not easy to find and they do tend to get snapped up when they are available.
"I would need to know what Birmingham's thoughts on the future are, whether they are in the Premier League or Championship.
"I fear they will want to keep things spinning along until the last moment, about May 5th-6th, but I'm not certain that will suit us."