Cervelli slid home, Wolters swiped his glove and tagged out Cervelli. It appeared that the play at the plate kicked up a clump of dirt, which struck Nelson in the left eye.
Pirates assistant athletic trainer Ben Potenziano ran out to check on Nelson. After tending to his eye for several minutes, Nelson left the field and did not return, leaving a three-man crew to officiate the game.
First-base umpire Ben May took over behind the plate, and third-base umpire Doug Eddings became the acting crew chief.
Adam Berry has covered the Pirates for MLB.com since 2015. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.