The thing is, the midfield is crap and is getting mauled, so the opposition gets the inside 50s, putting extra pressure on the backline. Grimes is there, but he has no one to pass to within an effective range or in a good position. The gameplan out of the backline is based on maintaining possession until you get a run out, which is very, very basic. Most clubs do it. But the midfielders don't present well enough, and so we find out half-forwards leading up into the back flank, and we're losing in the air so it just goes back into the forward line.
Grimes is just not being provided with a clean passive possession out of the backline, because no one is presenting.
And how kick-ins are a joke. Everyone is scared to present out of fear of error. That displays lack of leadership.