"The plan is to join in tomorrow or Friday if there are no hiccups," Johnson said in the Birmingham Evening Mail.
"I was hoping to be back a couple of weeks ago but I broke down, which was very frustrating."
"I think I was building up a head of steam before the injury. It took a while for me to settle in here but from pre-season onwards I've found my feet.
"I don't expect to go straight back into the team.
"I just hope I can get fully fit to start challenging again. It might take me a week or two to get right, the length of time I've been out I will need 90 minutes or whatever in the reserves.
"That's down to the manager. I'm just happy that I'm not too far away."
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