Influential defender Johnson appeared to be caught in the throat by the flailing arm of Crystal Palace centre-back Claude Davis and had to be taken to hospital.
The incident caused a half-time bust-up which saw both Dave Jones and Eagles counterpart Neil Warnock sent to the stands for the second half.
Chopra hobbled out of the action after 37 minutes and he faces a late fitness test.
Jones' men were in for training on Sunday, and he said: "There are one or two with knocks and bruises. We will assess how they are and then look towards the Burnley game."
Joe Ledley returned to the starting line-up against Palace after being rested for the Derby game, while Ross McCormack took his tally for the season to 21 goals with a brace and he should continue in attack.
Burnley striker Steven Thompson will miss the Clarets' clash with his former club.
Thompson was carried off on a stretcher with ankle ligament damage during the 5-0 home win over Nottingham Forest on March 14 and manager Owen Coyle has confirmed he will not return against the Bluebirds.
Goalkeeper Brian Jensen needed five stitches in an eye wound sustained in training on Friday but went on to keep a clean sheet in the Clarets' 1-0 win against QPR on Saturday and will continue.
Jay Rodriguez was handed his full debut against the Hoops with Martin Paterson struggling with tight hamstrings.
Paterson came on for the last five minutes and will hope to reclaim his starting spot on Monday.
Graham Alexander recovered from a calf strain to play the full 90 minutes on Saturday and will keep his place.
Sporting Life