The 23-year-old was forced off late in last week’s 2-2 draw at Albion and boss Dean Smith has confirmed he will not be available for the visit of the Potters.
Grealish is set to undergo a scan on Friday and Smith hopes he will be back for the busy Christmas period.
Smith said: “Jack has got a shin injury. He won’t be available for Saturday.
“But we are assessing it and hopefully getting another test done tomorrow. Hopefully he will be available for the Christmas period.”
Neil Taylor is also set to be sidelined for a fortnight with a hamstring injury sustained against the Baggies.
Albert Adomah is, meanwhile, still to fully shake-off an ankle problem, though Smith hopes the winger, Henri Lansbury and Birkir Bjarnason could all return for the visit of Leeds on Sunday week.