Boston Red Sox first baseman Mike Napoli revealed Tuesday that he has avascular necrosis in both hips, the same degenerative condition that ended the career of two-sport star Bo Jackson. But Napoli said that because the condition was discovered in its early stages and is being treated with medication, he sees no reason why he can't play this season. Avascular necrosis, known by its acronym AVN and also known as osteonecrosis (ON), is a progressive, degenerative disorder that kills bone tissue. According to AVNSupport.org, it is caused by a blockage or loss of blood flow to a joint or bone, causing the joint/bone to die.
