Those doubts were erased Thursday when the 6-foot-9 right-hander threw a bullpen session during the Rays' workout and all went well. He threw more than 40 pitches and used all of his pitches while doing so.
"I felt pretty good about what we did over the break and the last day of treatment here," Niemann said. "It was already feeling better. It was very encouraging to go out there and throw well."
Thursday's session offered Niemann a little peace of mind.
"I feel fortunate that we caught it at the right time," Niemann said. "I think we did the right thing by coming out. It was the right move, not that I wanted that to happen. But it was smart."