West Brom boss Tony Pulis will assess the Baggies' deepening injury crisis after he shelved their day off following a narrow FA Cup win at Peterborough.
Albion broke brave Posh's hearts to win 4-3 on penalties after being held to a 1-1 draw following extra time on Wednesday.
Ben Foster saved from Lee Angol and Martin Samuelsen in the shoot-out to earn the Baggies a fifth-round tie at Reading, despite Darren Fletcher missing from the spot.
Jon Taylor had put Posh ahead only for Fletcher to level in normal time during the fourth-round replay at London Road.
But victory came at a price after Gareth McAuley limped off with a hamstring injury and he is likely to be out for at least two weeks.
Albion are also waiting on the fitness of Jonny Evans, Chris Brunt and Craig Dawson while James Morrison and Callum McManaman are long-term absentees ahead of their trip to Everton on Saturday.
Pulis said: "We're more concerned with injuries, that's our biggest problem at the moment. They were going to have a day off on Thursday but we'll bring them all in so we can assess the damage and move on from there. Everyone is in.
"It'll be to check they have looked after themselves, they need to do stuff and we need to do stuff to them to get them ready for Saturday, we won't be training."
Albion had only won three of their previous 15 games in all competitions, drawing 2-2 with Peterborough at The Hawthorns in the first tie, but Pulis felt they could have won before penalties.
"We had the better opportunities as the game went on, we were just waiting for the net to bulge with Saido's (Berahino) header at the end and how he misses I don't know," he said.
"You have got to give all the credit to Peterborough. I am a traditionalist, I love this competition, it's very special to me in lots of ways. It brings back memories of being a young boy in Wales."
Posh are eighth in Sky Bet League One and boss Graham Westley was proud of his players in defeat and did not blame Angol or West Ham loanee Samuelsen for their penalty misses.
"They showed what good quality players they are. It's a young squad but a squad packed with quality," he said.
"You saw an attacking thrust and if they keep working at the rate they are they will not be League One players for long.
"Anyone can miss a penalty and both Martin and Lee showed courage to go up there. Both will have learned. Fletcher missed, an experienced player cracked under pressure, and I don't think you ever want to dwell on those moments."