Arizona Diamondbacks pitcher Zac Gallen left his Friday start in the sixth inning at Seattle with what the team described as right hamstring tightness.

Gallen walked the Mariners' Josh Rojas leading off the sixth, and after Julio Rodriguez fouled off a 1-1 fastball, Diamondbacks manager Torey Lovullo and a member of the team's training staff came to the mound to check on Gallen, who had thrown 64 pitches.

Lovullo signaled for Scott McGough to come in from the bullpen, and Gallen walked to the dugout with the trainer. Later in the sixth inning, Seattle's Mitch Haniger broke open the game with a grand slam.

Gallen (3-2) took the loss as the Diamondbacks fell 6-1. He was charged with three runs on three hits and one walk in five-plus innings. He struck out three.

An All-Star last season, Gallen has a 3.38 ERA through six starts this year.