William Hayes out for season with torn ACL in his right knee
"It hurts," Gase said. "He's one of our leaders in the locker room. ... That's going to be a tough one to swallow."
Hayes, 33, recorded two sacks during Miami's 3-0 start. He is in his second season with the Dolphins after four years with the Titans (2008-11) and five with the Rams (2012-16). He has 37.5 career sacks in 137 games.