This is definitely an issue with the team, and so is Stott. Especially since part of the Rojas experiment was contingent on the C and 2B providing a higher level of offense. Obviously Marsh is in a big slump too, and Turner, but I'm more confident in both of them.
Walker's just a red herring too, though obviously Allard could have done this just as easily. But as the Inquirer article noted today, the Phillies when they were on their way to 114 wins had a 2.65 rotation ERA (and that included 8 of Walker's starts). Since then, as they've gone 25-30, it's been 4.54. Which also makes every failure to score 5-6 runs or every bullpen glitch more noticeable.
But... get Suarez back at a solid level (to expect what he was in the first half probably not reasonable) and that will help. Sanchez might be the single biggest question mark (6.63 ERA in his last seven starts and he's approaching career-high innings).
All of which is to say, this team can still afford to take a few bullets if Walker pitching and/or a six-man rotation makes Suarez and Sanchez (and Wheeler and Nola) better in October. If that doesn't happen they are doomed anyway.
And yeah - this is almost every team in baseball right now, even if the Phillies have been genuinely awful for 15 or 20 games.