Hernández started on Opening Day again on April 4. He would lose for the first time ever on Opening Day, pitching six innings, walking five and striking out six. He gave up three runs, one earned. Two starts later at Yankee Stadium, Hernández tied Randy Johnson for most strikeouts as a Mariner, with 2,162, striking out Didi Gregorius looking for the final out of the fifth inning. The next start, Hernández surpassed Randy Johnson's record for most strikeouts by a Mariners' pitcher by striking out Rafael Ortega of the Los Angeles Angels for the second out in the bottom of the first inning. On May 9, Hernández recorded the 146th win of his career against the Tampa Bay Rays, surpassing Jamie Moyer for most wins as a Seattle Mariner. On June 1, Hernández was placed on the 15-day disabled list due to a right calf strain after jumping up to celebrate a home run. On August 15, Hernández earned his 150th career win, defeating Mike Trout and the Angels by a score of 3–2. This milestone win occurred on the fourth anniversary of his perfect game.