Return to play: making the tough decisions.

When can I play again?" is a question familiar to sports medicine physicians and increasingly to primary care physicians who treat active people, from the third-grade soccer player to the 70-year-old tennis enthusiast. Those who ask this question are often seeking a definitive answer-and usually hoping for a quick return to boot. Unfortunately, medicine is not always a craft practiced in black and white but is often an art with a palette in several shades of gray.