As recently as a week ago, Mike Mussina was the rock of the Yankees' starting rotation. Now, his season might be over. The Yanks and Mussina downplayed that scenario yesterday while discussing the righthander's ailing elbow, but no one could rule it out. Mussina traveled to Los Angeles early yesterday to have the elbow examined by specialist Lewis Yocum, and after conducting an MRI and X-rays, the doctor confirmed that Mussina has inflammation that is likely due to tendinitis. At this point, rest is the only way to heal the condition and Mussina admitted he has no idea when he will be able to pick up a ball again. Once he feels well enough to begin playing catch, Mussina will need about seven to 10 days to get in game shape, he said, and with only a month remaining in the season, there is an even greater urgency for him to return quickly. When asked to describe his level of worry about whether he'll return this season, Mussina said, "I don't think it's a significant amount of concern. It's a possibility, I guess, but not a significant amount of concern."