The midfielder, on-loan at The Hawthorns from Chelsea, will be ineligible to face his parent club, despite impressing on his West Brom debut against Brentford on Tuesday.
Branislav Ivanovic continues to build up his fitness but is unlikely to be ready in time to face his former club, while manager Slaven Bilic will also be without suspended full-back Kieran Gibbs following his red card against Everton on Saturday.
Christian Pulisic and Hakim Ziyech will miss out for Chelsea.
Pulisic continues to nurse a hamstring issue, while Ziyech has not yet shaken off a knee complaint.
Chelsea boss Frank Lampard has said the Hawthorns trip will come too soon for new recruit Edouard Mendy to start, leaving Kepa Arrizabalaga and Willy Caballero to battle it out for the goalkeeping berth.
Provisional West Brom squad: Johnstone, Furlong Ajayi, Bartley, O'Shea, Townsend, Costa Pereira, Livermore, Sawyers, Diangana, Robinson, Robson-Kanu, Phillips, Harper, Edwards, Kipre, Button, Field.
Provisional squad: Arrizabalaga, Caballero, Mendy, James, Azpilicueta, Alonso, Chilwell, Zouma, Christensen, Rudiger, Silva, Tomori, Kante, Jorginho, Kovacic, Loftus-Cheek, Barkley, Mount, Havertz, Hudson-Odoi, Werner, Abraham, Giroud.