The Norwegian international missed the weekend win over Doncaster Rovers with a slight hamstring strain picked up in training, but if he has no further problems he could be back for the Etihad clash.
Gary Bowyer has a strong squad at his disposal with just Corry Evans and Dickson Etuhu, both out with ankle ligament injuries, absent.
Speaking on Monday, the manager said: "Josh King trained on Monday and if he trains well on Tuesday then he should be back.
"Corry Evans is making good progress, we expect him to return to training with the group at the end of the week."
The manager may opt to shuffle his pack for the replay, but knows that his squad are all eager to play.
"The mood is one of excitement," added Bowyer. "We asked them who wanted a rest and we didn't get an answer so they are all wanting to play in it, that tells you how far they have come so quickly."
Tickets for Wednesday night go off sale in the town centre store this Tuesday at 2.00pm. They go off sale at Ewood at 4pm Wednesday. Should tickets still remain then they will be on sale from the Etihad Stadium on the evening of the game. Tickets are priced from £15 Adults, £10 Seniors/16-21yr olds and £5 Under-16s. Call the ticket office for further information on 0871 222 1444.