Cousins was removed from Thursday's game against the Mariners due to right pectoral tightness, Gary Phillips of the New York Daily News reports.
The Yankees' training staff saw something they didn't like after Cousins struck out Julio Rodriguez in the sixth inning, and they made the decision to pull their right-hander after he recorded just one out. The team will take a closer look at Cousins in the clubhouse to determine the severity of his injury, though he may be unavailable out of the bullpen for the next couple of days.