The New York left-hander was struck by Mark Ellis' shot in the third inning Tuesday night. Niese hopped toward home plate looking for the ball and then sat down in the dirt along the first base line.
He was grimacing as manager Terry Collins and a trainer looked at him. Niese was helped to his feet and exited, hopping down the steps leading toward the clubhouse.
Niese began the day with a 2-1 record in four starts. He gave up one run on three hits and three walks in 2 1/3 innings.