The lanky right-hander was forced to miss Sunday's loss to the Toronto Blue Jays, prompting the team to send him back to St. Petersburg, Florida, to have his shoulder examined further.
Manager Joe Maddon told the team's website (tampabay.rays.mlb.com) that the injury has been brought on by "muscle fatigue," and that he does not expect his starter to be out of the rotation for long.
Niemann has a 10-3 record with a 3.12 ERA and has been solid for the Rays (68-44), who are currently one and a half games behind American League East leaders the New York Yankees.
The Rays beat the Tigers 6-3 on Monday in the first of a three-game series in Detroit.
(Reporting by Jahmal Corner in Los Angeles; Edited by Patrick Johnston)