Williamson injured his right knee in Friday's match while fielding near the boundary when he leapt to stop a six. He saved two runs as he palmed the ball into the field but landed awkwardly, falling to the ground clutching his knee.
He had to be helped off the field as Gujarat brought on Sai Sudharsan as an "Impact Player", a new rule the IPL brought in this season which allowed the 21-year-old Indian to bat at No. 3 instead of Williamson during the run chase.
Gujarat did not mention who would replace Williamson in their squad. The team, who are the reigning champions, won that match by five wickets.
On Saturday, New Zealand head coach Gary Stead said it was "too early to know" whether Williamson had done significant damage to his knee that would rule him out of the 50-overs World Cup to be held in India from October this year.
