Really looks like some key players on offense (Turner and Harper) have been playing hurt much of the year and avoiding 100% sprints. Plus the pitching is hitting a bit of a wall. Some of the younger pitchers like Sanchez and Suarez are up against new inning limits and not as good as they were earlier. Nola and Wheeler have also been inconsistent.
These are all solvable problems, though the team is probably not as good as they played in the first half. Most teams have issues so getting key players right by September is still the priority. Frankly if they can get some innings from Walker this week it might go a long way to easing everyone's trepidation. There is probably not much confidence in Allard and Phillips, so getting positive innings from another trusted source would be a good thing.