The Tykes entertain Gillingham tomorrow at Oakwell and sit just two points off the League One play-off places.
Some Barnsley fans have voiced their concerns about playing a lone striker as they chase promotion back to the Championship.
But head coach Johnson said: “I think they’re wrong. We don’t set up to be negative, we set up in different shapes and formats this season trying to find the right blend.
“There’s a natural instinct for people to say, and I’ve heard it on the radio, ‘why is he playing one up front?’ but we set up a game to win.
“We don’t set up to draw, we set up to win, and in our group at this moment in time, I believe that our best opportunity of winning the games is to play three in midfield.
“I say that formations don’t matter. If you’re playing to the style and the philosophy, I call it 5-5-5 because we’re trying to create numerical advantages all over the pitch.”
Following the 1-1 draw at Blackpool last weekend, Johnson has been able to enjoy time on the training ground with no midweek match.
He said: “It’s always good when you can get that extra tactical or fitness work. It’s important we keep those squad members, or those who have not been playing regularly, topped up and ready to go.
“We’re going to need them and we may make changes this weekend and we need to know that they can last the 90 minutes.”
Barnsley have no new injury problems ahead of tomorrow, with on-loan midfielder Dan Crowley back in training.
He said: “We’re looking okay. We don’t have any serious injuries from the game at the weekend. Dan Crowley should be back for us.
“He is training (yesterday), which is good, hopefully we’ll come through with no problems and he should be back in the squad for Saturday.
“We aren’t quite full strength because Ryan Williams is still not there yet, he’s up and down like a yo-yo with his groin.
“One minute he’s fine, the next he’s struggling and it’s something we’ve got to get to grips with because he could be an important player for us.”
Rotherham United want to extend the loan deal of Norwich City midfielder Vadis Odjidja-Ofoe after his current one-month deal expires.