"You've got to know it can take contact and a lot of the time, it's not so much the contact, it's the way you do the injury.
"For Foz, he can put his shoulder into a tackle and its' fine, but for Foz, it's landing and making sure that he can take the contact on his elbow when he hits the ground.
"So there's 'fit and ready to go', but there's also upstairs as well, where you need to be mentally ready and not doubt it."
Johnson speaks from experience gleaned the hard way. His 2015 season was curtailed, when his ankle was shattered in a tackle and he admits it took a while before he felt confident that it wouldn't happen again, even when he was back to full fitness.
"I'm speaking from my history of injury and I've spoken to Foz about his. It's not so much the contact, it's the way you do the injury.
"For me, I know my ankle is strong, but it's the thought of someone coming down on it that same way ..."
Johnson insisted the Warriors were putting no pressure on Foran to come back before he was absolutely ready.
"We're not saying 'we need you back'. We want him to be right, we want him to be 'confident Foz', when he comes back."
In the meantime, Johnson's growing comfort with rookie Ata Hingano has been one of the biggest positives to come out of the Warriors this young NRL season.
Listen: Shaun Johnson on the Radio Sport Breakfast
"We're learning, we're growing as a combo every week and we're putting a lot of work into that at trainings.
"I know when I was coming through, I don't just want to throw too much at him and I know the coaching staff are mindful of that. You want him to just be nice and clear and calm, and to just worry about doing his job.
"If we're on the run, he needs to feel comfortable enough to step up, call a play and then I can react to that. It's real cool to see him grow and feel comfortable in that role."
The Warriors - and Johnson in particular - are looking forward to playing within the sheltered confines of Dunedin's Forsyth Barr Stadium tomorrow, especially after last week's horrific downpour at Mt Smart Stadium.
"I've played down there a couple of times now," said Johnson. "It's obviously good knowing the conditions will be dry.
"I know sometimes the wind can actually swoop in from one end and create a bit of a breeze, but apart from that, when you've got it ready for you to just turn up and play, without having to think about conditions too much, it is a lot easier.
"We'll definitely be letting the ball go a lot more than we did this week and hopefully we can express ourselves a bit better that way."