Cech finished Wednesday night's 3-2 victory at Blackpool with a hamstring problem, while substitute striker Miller injured his ankle in the challenge that won Albion's match-winning penalty late on.
Fortunately, the injury sustained by fit-again Miller has nothing to do with the knee problems which forced him out of the game for 13 months.
Key players Chris Brunt, Roman Bednar and Jerome Thomas were all substituted prior to the 75th minute at Bloomfield Road with Roberto Di Matteo maintaining one eye on the trip to Home Park.
The Baggies stayed in Lancashire following Wednesday's fine win - a result which extended their unbeaten run to five games - and will fly straight to Devon on Friday to avoid lengthy coach travel on the motorway.
Deadline-day signing Andy Slory will again look to make an impact from the bench as he did against the Seasiders.