The Norwegian international missed Saturday's Ewood draw with Derby County after sustaining a knock, but having shaken that off he is back in contention for the match at Oakwell.
King has had a good time of late against the Tykes, scoring the opening goal in Rovers' 3-1 win in the corresponding fixture last season, whilst this term he grabbed Rovers' fourth goal in the 5-2 win back in August.
But as manager Gary Bowyer confirmed King's return, one player absent at the weekend who won't be available is captain Scott Dann.
Speaking on Monday afternoon, Bowyer said: "Josh trained today so he comes into contention for the game.
"But Scott Dann failed a fitness test on Saturday and he hasn't trained today either. So he won't be involved on Tuesday.
"Corry Evans returned to training today and joined in with the lads again. So he'll have a full week this week and next week, and now the game against Brighton has been called off we certainly hope him to be back in contention for the Reading game.
"Dickson is on his rehab now so he's getting closer, so aside from Ben Marshall we've got players coming back, it is just a case of keeping them fit.
"I think everybody else has recovered well and we are ready to go again on Tuesday against Barnsley."
Tickets for Barnsley will go off sale at Ewood at 4pm on Tuesday, after that they'll be on sale on the night at Oakwell.
Prices are £23.00 Adults, £16.00 for Seniors (aged 65+), Under 18s and Students. £5 for Under 12s.
Fans should note that neither student priced tickets nor Under 12s tickets are available on the day of the game. Under 12s tickets MUST be purchased with an adult/senior citizen ticket.
Students MUST be aged 18 to 20 years and produce a valid student card with photo ID and proof of D.O.B on entry at the turnstiles.