The summer signing had only just returned from a hamstring complaint when he damaged the joint during Saturday's 2-2 draw with Aston Villa at The Hawthorns.
However, manager Steve Clarke is hoping that the problem does not keep the Argentine out of action for too long.
"He's damaged his shoulder. We are not sure how serious it will be, so it's fingers crossed," he told the Express & Star.
"We have got 10 days until the next game and we are hopeful we will get a few more players out of the treatment room."
Yacob has made 15 appearances in all competitions this season.