OK, then let me educate you.
https://www.baseballamerica.com/stor...ing-into-2019/
"Once the problem was properly diagnosed as shoulder inflammation in his subscap muscle"
The rotator cuff consists of the supraspinatus, infraspinatus, subscapularis and teres minor muscles.
The subscap is responsible for stopping the humerus (upper arm bone) from coming out of the shoulder socket when forced forward...aka throwing a baseball.
As I said, shoulder issues are the scariest injuries for pitchers, and it isn't even close.