Fredericks, who also won the Continental Cup and African titles during a breakthrough 2014 season, would be sidelined from training for up to six weeks, due to tears in his right Achilles.
“Depending on his rehabilitation the earliest he will be able to race again could be mid-June, maybe even later,” the HPC revealed in a statement.
Having won the national title four times in the last five years, Fredericks admitted he was disappointed not to be able to turn out in Stellenbosch.
“It will be the first time since 2005 that I will not compete at a national championship,” he said.
“It is one of only a few opportunities that I get to race in front of my own people and it is therefore very special.”