Lowder was removed from Thursday's game against the Cubs with right shoulder discomfort, Charlie Goldsmith of Fox 19 Now Cincinnati reports.
Lowder was able to make it through three innings Thursday, giving up one earned run on a solo homer from Michael Conforto. Lowder came out for the start of the fourth but was visited on the mound by a trainer after walking the first two batters he faced in the inning. The severity of his injury remains unknown, but the Reds may send the right-hander in for imaging to determine whether he's dealing with a structural issue.