The German, who dominated women's tennis over the past decade and won seven Wimbledon titles, has had to withdraw from the forthcoming Italian, German and French Opens because of an ankle injury.
She had two operations on her knee last year and has not fully recovered from the groin injury she sustained at the Indian Wells tournament in California in March.
"I am at the point where I can clearly see the end of my career," Graf told Focus magazine after slipping to 33rd in the world rankings. "If I have one more little injury I will stop.
"I've been going up and down constantly for the past two years. Every time I struggle to reach my old form after an injury, another injury throws me back into the role of a patient.
"I will prepare carefully for the next attempt. But if I can't establish any continuity in my practice or tournament schedule, I will give up," she added.
But the 28-year-old still has one tennis dream - to finish her career with another victory at Wimbledon.