Shortly after kick-off, the hybrid centre challenged Harri Millard for the ball in an aerial contest but landed awkwardly on his right foot.
Esterhuizen remained on the ground as the Sharks' medical staff rushed on to assess the injury. Although the Springbok star eventually got back to his feet, he was unable to put weight on his injured foot and had to leave the field, with Jaco Williams coming on as his replacement.
The injury will be a concern for Springboks coach Rassie Erasmus, who is expected to announce his squad for next month's Nations Championship tour to the United Kingdom and Europe in the coming week.
The world champions will face Italy in Turin on 7 November before taking on France in Paris on 14 November and Ireland in Dublin on 21 November.
Esterhuizen, who is also capable of playing on the flank, has become an important figure in the Springbok setup thanks to his versatility, regularly switching between the backline and forwards.
Sharks coach JP Pietersen praised his players' resilience after they overcame a string of injuries to down Cardiff 36-21 in their United Rugby Championship clash at Arms Park on Friday night.
The Sharks earned an entertaining 36-21 win away to Cardiff in the United Rugby Championship clash in Wales on Friday night.
The Sharks are riding a wave of positivity as they arrive in Cardiff for their fourth-round United Rugby Championship match on Friday night.
Springbok star Cheslin Kolbe will miss South Africa's end-of-year Nations Championship tour, but his return-to-play date has been confirmed.
