The guard experienced tightness in his left hamstring during Tuesday's defeat to the Houston Rockets.
Head coach Gregg Popovich told the San Antonio Express-News: "What can I tell you, it is frustrating, but I don't know what we can do about it. We just got to get our other guys to step up and play. You know, they're trying. That's all I can ask of them."
Ginobili has averaged 12.1 points per game so far this season.