Durant has not played since suffering the injury in a 104-99 win over the Houston Rockets on May 8. Golden State is 5-1 without Durant in the lineup.
"When he's ready to play, he'll play, and that's our approach," Kerr told reporters Friday.
Kerr also said forward Andre Iguodala had an MRI on his left leg Friday. Kerr didn't have the results, but said Iguodala "seems to be doing well."
Durant averaged 26 points per game this season. He was averaging 34.2 points per game in the playoffs before his injury.
Golden State is down 1-0 in the NBA Finals after a 118-109 loss to Toronto on Thursday night. Game 2 will be played Sunday night.