According to Cleveland Indians beat reporter Jordan Bastian, outfielder Michael Brantley received an anti-inflammatory injection in his right shoulder today. Brantley has been diagnosed with a subacromial impingement (also known as "swimmer's shoulder"), and there is currently no timetable for his return.
The full statement from the Indians, via Bastian, can be seen below:
— Jordan Bastian (@MLBastian) May 17, 2016
From what my Google-foo can tell me, a subacromial impingement is essentially an "abnormality" in the rotator cuff that causes the bursa sac to rub up against the top bone of the shoulder at an awkward angle and causes pain.