Thompson was a game-time decision and pushed to play Wednesday, but the Warriors' staff ultimately held him out of the lineup as a precaution.
"Well, the whole point was to not risk a bigger injury that would keep him out of the rest of the series," Kerr said. "That was the decision we made, and I feel very comfortable with it. [I] never would have forgiven myself if I played him [Wednesday] and he had gotten hurt. So you live with the decision you make. You make a wise decision, the wisest one you can, and then you live with it and move forward.
"The good thing is, Klay has done well the last two days. Now, he has a couple more days to heal, and hopefully he'll be out there on Friday."
Thompson suffered a left hamstring strain in the fourth quarter of Game 2 after landing awkwardly on a jump shot. He exited the contest and didn't return.
As for Durant, Kerr told reporters before Game 3 that the superstar forward is doing more in his workouts and could participate in 3-on-3 scrimmages Thursday. The coach said it was "feasible" that Durant could have one day of practice and be cleared to play.
Golden State has a practice scheduled Thursday ahead of Friday night's Game 4 in Oakland, Calif.
Durant suffered a right calf strain May 8 against the Houston Rockets in the Western Conference semifinals and hasn't played since.