Regarding team news, Johnson is without Milan Lalkovic for three games following his straight red car at Leyton Orient, but is boosted by the return of Jean-Yves M'voto and Peter Ramage, he said, "We're looking all right. There are no fresh injuries. Big Jean-Yves M'voto had a little bout of sickness so he missed the last game, but he's okay now. We gave him 45 minutes in the Under 21s to sharpen him up a little bit and he looked good.
"He comes back into it and makes us stronger again."
Fellow central-defender Peter Ramage also returns from a hamstring injury, and Johnson is most likely to include the Crystal Palace loanee in Saturday's squad.
"He's doing well. He's gained two full days now. Probably not quite ready for a start but certainly could be used for the bench if needed. He's definitely available.
"We want as many players back playing and available as we possibly can. The problem we've got is six loans and one of them will have to miss out. If we sign anyone else on loan two might have to miss out so we have to be careful of that. When you've got a lot of bodies training, it's a good things because it means there's competition for places and nobody feels like their place is guaranteed."
Johnson admits Saturday is probably the last time Barnsley fans will see John O'Sullivan in a red shirt, with Blackburn boss Gary Bowyer saying the winger will return to Ewood Park after his loan expires.
"It's disappointing for us, of course, because he's done well. But that's the plan for them - get him out, let him do well and come back for the back-end of their season. We may have to do a little bit of work to replace him in the market.
"It's not the lad's fault, it's not a case of him not wanting to be here. He's been recalled by his parent club.
"In an ideal world we need somebody to replace John. He's done very well and it's an opportunity to sort of tinker and bring somebody in if it's right to. If it's not, we won't. They have to be ready and raring to go. We're certainly on the case, you can trust us on that.
"We're chipping away and people have to trust us. We're constantly scouring the market. It's a constant evolution of a football club."
Turning his attention to the next three games, starting with Preston, Johnson added, "Four or five weeks ago I wouldn't have thought too many people were getting excited about this time. To get these next three games against top six teams are exciting. If you're not excited as a player, you may as well give up now because we're sixth in the table. We're up there and up there on merit. We're in form, playing well and everybody is behind us. That's the sort of atmosphere, surely, you want to play in as a player.
"Every win you get - not necessarily result - is massive at this stage of the season. Not only do you gain three points but you lose a game and if anybody slips up with three, four or five games left, it's difficult for anyone else to come over the top of you.
"I think it's quite an interesting scenario. Do you fight harder being the challenger or as the champion? Of course, you should fight equally as hard as both. It is a different mindset and we mentioned this to the players. All of a sudden when you're there to be shot at, you have to have that mental character.
"Preston are a strong side. Their squad is strong. They've invested heavily in that squad. They had a good year in League One last year as well and they have a good manager who knows the division.
"They're coming here and we'll certainly not lay down and die."
