He did not practice Wednesday or Thursday.
"Well, more than likely,'' Rivera said when asked if the team's leader in sacks (8.5) would not play against the Dolphins. "It's one of those things we'll see how he is tomorrow. I was a little discouraged today because he didn't go out on the field earlier.
"He has gotten better each day. But again, you like to have guys out as soon as possible and go from there.''
The league's third-ranked defense has given up 1.5 yards more per play when Johnson is not on the field this season, but Rivera doesn't expect a drop-off if the former Georgia star can't go.
"Without a doubt,'' he said. "We've got a good group of young men. You'd like to believe when you get an opportunity guys are going to stop up.''
The Panthers also were without right defensive end Greg Hardy (knee) on Thursday after the fourth-year player complained of soreness during the morning walk-through. Rivera said it was a precautionary move and he anticipates Hardy to play Sunday.
The Panthers (7-3) have won six straight and seven of their last eight since an 0-2 start. Rivera was hesitant to say he would err on the safe side when making a decision on Johnson because the team might need him for late-season games and the playoffs.
"I don't want to say yes because all these games, each one is important,'' Rivera said. "You want to win them [all], and you've got to win now. But again, we've got to be smart. We've got to make a really good decision, and he's got to be honest with us.''