Tau, who has just returned to training after a three-month lay-off because of a fractured left ankle, will now have to contend with a toe injury on his left leg.
According to Chiefs coach Stuart Baxter, Tau is still not fully fit after the discovery of the toe injury.
"Jimmy is still not 100%. The bad ankle injury is almost rehabbed, but there is a complication with one of his toes," Baxter discloses.
"We have him at training, but (the toe) is not improving at the rate we would like so we are sending him back for another assessment," he adds.
Tau was expected to fill in the void at right back following the ankle injury Siboniso Gaxa suffered in a clash with Bidvest Wits on Monday.
However, Kgotso Moleko or Lincoln Zvasiya can play the role.