Cabrera appeared to be squaring to bunt on the first pitch from the Royals reliever, who had just replaced starter Yordano Ventura. Cabrera was late to recognize the pitch was inside and leaped back as it hit, dropping him to the dirt.
The Blue Jays' left fielder rolled around in pain on the grass down the third-base line while Duffy crouched behind the mound. Cabrera was eventually helped off the field, through the dugout and to the visiting clubhouse, and X-rays came back negative.
Blue Jays spokesman Mal Romanin said Cabrera was day to day.
Jonathan Diaz entered for Cabrera as a pinch runner and went to left field in the bottom half.