However, Foster has revealed that he has no concerns about Clarke's ability to convince players to join the Black Country-based outfit.
"It's a tough one. We have got quite a settled team at the minute which is nice. There are quite a few teams that could go either way next season," said Foster.
"But we have got a settled bunch of players and we are well drilled. We know what to expect from each other and that's going to help us. It's up to the manager whether or not he wants to add to the squad and, if he does, what sort of players he wants to add.
"I'm sure we'll roll with that because we trust the manager and the players we brought in earlier in the season have been good acquisitions. We trust him to do the same again next season."
Foster joined the Baggies on a permanent deal from Birmingham City last summer.