On April 17, 2019, Gardner hit his 100th career home run—a grand slam off Ryan Brasier—to give the Yankees a go-ahead 5–3 lead over the Boston Red Sox in what would be the game-deciding hit. He became one of two players in Yankees history (alongside Derek Jeter) to hit at least 100 home runs and steal at least 250 bases. On July 26, the Yankees placed Gardner on the 10-day injured list (retroactive to July 22nd) for left knee inflammation stemming from an injury he had suffered the previous week, putting him on the injured list for only the third time in his major league career. He was recalled from the injured list on August 2.