What is rotator cuff tendonitis?
First, tendons are bands of connective tissue that attach muscle to bone. Thinking of them as taught rubber bands is a good visual. Tendonitis is an inflammation (irritation and swelling) of a tendon.
The rotator cuff is the collection of tendons that hold the humerus (the large bone between the shoulder and elbow) together with the scapula (the shoulder blade) and move the arm up and forward.
The common causes of tendonitis are overuse and age-related issues (tendons become less elastic and more prone to inflammation and irritation as we age). Sometimes, when the tendon fails to have a clear or smooth path upon which to glide, tendonitis in strong, young tendons can occur.
In my (layman's) opinion, there are 2 possible sources of Joba's tendonitis:
1. It's possible that the switch from reliever to starter could have resulted in this tendonitis. Having potentially grown accustom to throwing between 30 and 60 pitches (including warm-ups) as a reliever and then changing to 100-140 pitches (again, including all pre-game and pre-inning warm up throws), the tendon could have become over-worked and inflamed.
2. Something such as a bone spur on the ball of the humerus could be irritating the tendon. I imagine that this was one reason that Joba saw Dr J Andrews (the other being confirmation of no tear in the rotator cuff). If a bone spur had formed on the ball of the humerus the tendon would continue to rub against it and get inflamed over and over.
What does all this mean to us, the fan?
We will probably not see Joba again this year. I say this not because the injury itself is particularly serious, but each occurrence brings a higher potential for additional recurrences going forward. Given the Yankee's bent for treating youngster's injuries extremely carefully, I think he'll be out till '09.
If Joba endeavors on a program to strengthen the muscles of the rotator cuff and there is no structural abnormality (i.e.-bone spur) causing it, a tendonitis repeat can probably be avoided. While this isn't what we hoped would happen, given the circumstances it might be the case best scenario.