The Dockers are the number one defensive side in the competition this season but they will need to contain the electric, and eclectic, Carlton forwards who combined for 42 scores from 65 inside 50 entries in the Blues 43-point win over the Gold Coast last Saturday.
"They have been in good form in the last couple of weeks," Johnson said at a press conference on Tuesday.
"We know that they've got the pace and skill and they love to get out the back, so we'll have a plan to match them."
Eddie Betts, Jeff Garlett and Chris Yarran have combined for 14 goals and 10 behinds in their last two matches, and Johnson believes the key to quelling their influence is to limit their opportunities to use their pace.
"You don't want to give up goal side against any forward," Johnson said.
"The best defence is to keep them in front of you, and body and check them. It's very important this week against the quicker players."
Johnson believes the Dockers defence has been outstanding in the absence of their 'General', Luke McPharlin.
The 2012 All Australian full back has missed the past three matches due to a calf tear and is still a number of weeks from returning.
The Fremantle defence managed to contain the Adelaide Crows to just seven goals from 45 attacking entries last Saturday night, something that Johnson felt was a real positive.
"We were under the pump on the weekend, but the way we fought against the Adelaide mids delivering the ball into their forwards, we can look at it as a positive," Johnson said.
The absence of McPharlin has provided significant opportunities for other defenders to fill the breach.
"We do miss him," Johnson said.
"(Zac Dawson) has stepped up and played on a couple of key forwards in the last couple of weeks.
"That's the bonus about this team. We can step up with key players out of the team."
The Dockers were criticised for winning last week with just 33 inside forward 50 entries.
Johnson believes the inclusion of Hayden Ballantyne this week, returning from a hamstring injury, will strengthen their scoring power.
"He's a leader down there," Johnson said.
"It sort of frees up Michael Walters a bit as well.
"So to have them running around in the forward line, I would hate to play against them."
