Albion full back Bernardo Fernandes da Silva Junior will miss both the Liverpool and Manchester United matches with a hamstring injury.
Gaetan Bong is likely to fill in for Bernardo in the Premier League fixtures.
Albion face Premier League leaders Liverpool at the Amex tomorrow (Saturday 12 January) at 3pm.
They take on Manchester United at Old Trafford a week later on Saturday 19 January.