A 32-yeаr-оld mаle cоmes intо your clinic with complаints of swelling and pain of his right shoulder. He tells you he plays softball every weekend and does a lot of hoeing and shoveling in his large backyard garden. The shoulder had been sore, now it hurts to the point where he tries to avoid using it. The drop arm test was positive. Which of the following conditions is the most likely diagnosis for this patient?