Lopez (undisclosed) exited Tuesday's start against the Nationals after one inning, David O'Brien of The Athletic reports.
Lopez pitched a scoreless first inning before meeting with manager Brian Snitker, pitching coach Rick Kranitz and a trainer. Lopez's velocity was down a couple notches in the frame and he was ultimately removed from the contest. It's unclear what the right-hander is dealing with, but more information on his status will likely be provided in the near future. In the meantime, Jesse Chavez replaced him on the mound against Washington.