Bruce felt some discomfort on a check swing during his second at-bat of the game. He immediately grabbed at his side and then asked for time before being examined.
Roman Quinn pinch-hit for Bruce and completed the at-bat by striking out before remaining in the game to play center field.
Bruce said postgame he injured the area near his right rib cage and will undergo an MRI tomorrow before determining the next steps, according to Matt Gelb of The Athletic.
Bruce has become a staple in the Phillies' lineup since being acquired from the Seattle Mariners in June. The 32-year-old owns a .230/.279/.546 slash line this year and has hit 10 of his 24 home runs with Philadelphia.