CJ Egan-Riley and Joe Newell were both forced off through injury during the second period, while fellow midfielder Jimmy Jeggo appeared to be carrying a knock during the first half of Wednesday night's 4-2 victory over Celtic at Easter Road and didn't reappear for the second 45.
Previewing the short trip across town as Hibs hope to upset their Gorgie hosts and sneak fourth from under their noses, Johnson admitted that the on-loan Burnley man wouldn't be fit for the final-day fixture.
"CJ will be out. It was his hamstring - he felt it the day before in training and didn't say anything because he wanted to play so much," the Hibs boss explained. "We are feeling for him because his mum up for the weekend and it would have been nice for her to see him play but that's football and you sometimes have to deal with these things.
"I think it was his left leg because of that punt with his right to put it out. But you could tell, because he was punching the ground. He's a good lad and we'll do whatever we can. Jimmy Jeggo's substitution was tactical on Wednesday. He did have a knock, but I expect him to be okay."
More concerning for Johnson and the Easter Road medical staff might have been Newell's enforced exit after 73 minutes of Wednesday night's six-goal thriller but the English midfielder should recover in time to play his 34th cinch Premiership fixture of the 2022/23 campaign.
"Joe is 75-25 in favour," Johnson continued. "It was two contact knocks on his shin [against Celtic] and normally they recover. He's looking more likely to be available."
The Hibs boss also hinted at a shock comeback for one long-term absentee as he seeks any advantage he can get going into the Tynecastle Park clash.
"Kyle Magennis is training but it has probably come a little too soon. Although I don't know, actually. I was sat there watching him on Thursday, and you know I like Kyle Magennis and the way he plays. Without any sort of minutes it would be extremely high risk but we may need a little bit of magic that he can bring."