He appeared to have hit his head on the ground, and remained down on the warning track for several minutes before getting to his feet slowly. Pirela was replaced in center by Slade Heathcott.
Pirela collided with the wall while chasing a ball hit by Juan Lagares from Yankees starter CC Sabathia that resulted in an inside-the-park home run.
Pirela, the Yankees' No. 25 prospect according to MLB.com, has been having a good spring, batting 10-for-27 with two doubles and three triples entering Sunday.
Jamal Collier is a reporter for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.