The Miami Dolphins ruled out edge rusher Chop Robinson ahead of their Week 2 matchup at San Francisco because of a concussion. Coach Jeff Hafley told reporters Friday at the team’s training site in Napa, California, that Robinson sustained the concussion at practice this week. He was held out of practice Thursday. Robinson’s absence Sunday could hurt a Dolphins’ defense that struggled to stop the run and generate pressure against quarterback Kirk Cousins in their Week 1 loss to the Raiders. Cousins completed 21 of 30 passes for 160 yards and three touchdowns, and running back Ashton Jeanty rushed for 102 yards on 23 attempts.