According to what the doctor's examination revealed, Niemann has some labrum and rotator cuff abnormalities. When given options for his treatment, he chose surgery.
"He feels he can't compete at this level without it," said Ron Porterfield, Rays head athletic trainer. "He feels like right now it's bothering him too much that he just doesn't have his confidence that he can do what he needs to do."
Niemann will have an MRI Tuesday and the surgery will likely take place on Wednesday. That surgery will "more than likely" end Niemann's season, Porterfield said.
Niemann declined to speak with reporters Monday night.
The 6-foot-9 right-hander experienced an injury riddled 2012 campaign when he opened the season as the team's fifth starter. First he suffered a fractured right fibula on May 14 when Toronto's Adam Lind hit a line drive off his ankle.
Niemann spent three and a half months on the disabled list. He returned to make just one more start on Sept. 1 in Toronto, but he pitched only 3 1/3 innings due to tightness in his right arm. That tightness was later diagnosed as slight inflammation in his rotator cuff.
He appeared to be back on track during Spring Training when he competed with Roberto Hernandez for the fifth spot in the rotation. He lost that battle despite pitching well and was assigned to work out of the bullpen.
Before he had the chance to pitch in a game this season, he was placed on the DL.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.