Dog doesn't understand gardening/is just playing as it thinks it should where it had been shown to do so. You won't need to do anything to the grass if you can find an alternate energy outlet for your dog besides running back and forth in the back yarden. The grass will come back with light seeding but you gotta stay off of it. He looks like a collie/shepherd mix so he needs to be chasing a ball, riding next to you on a bike walk, or playing at a dog park. All viable alternatives to keeping him from being destructive in back. No energy left at home is the goal.