The 29-year-old former national under-23 captain is currently without a team after being released by National First Division side AmaZulu at the end of last season.
Johannes, along with another ex-Buccaneer Lennox Bacela, has been training at City with a view of trying to impress coach Eric Tinkler ahead of the 2016/17 season.
"There are other foreign players also trying their luck," he added.
The Cape Town-born centre-back also had stints at University of Pretoria, Golden Arrows and Maritzburg United.
