Let's start off by talking about Ross. How did he do against a good team? Eh. You know. Not the worst. If you are a Ross lover, you are probably thinking "If they had a good RFer in then that Puig hit is no worse than a single and actually is probably caught and the night looks differently" Ok sure. But Ross was hanging junk all night and the Dodgers were missing it. Pop-ups usually happen on 98 MPH heaters up in the zone, not sliders and sinkers that aren't sliding and sinking. Watch the game again and see how many "Oh they really could have nailed that" pitches you see. I saw a fair amount.
If you're negative then you can say "this is Ross". You might think that is unfair, it's just one poor start, but the unhittable Ross with perfect control? That was the unusual Ross based on his minor league stats. If you're positive you can hang your hat on some good situational pitching like that Gonzalez AB in the 3rd where Ross found a spot he felt was a weakness and was able to pound it over and over. Even if you are like me and think the Ross-love is overblown, there is undeniable potential.
Mets win. Nats lose. Whatever. That'll happen. What can the Nats do to get better now? They got another top notch relief pitcher. They sat Fister for Ross. Desmond has hit his way to a point where he's mashing bad pitches from bad pitchers and not striking out all the time. What's the easiest way to get better today?
Unlike Ian, who is presumably healthy but working through issues, Jayson was hurt this year. He may still not be 100%, In fact I'd take all the money I have sitting around and bet on that fact. The guy is 36. He hit .208 / .294 / .287 before going out. He's hit .160 / .185 / .280 since. Just a bad two weeks? Perhaps. But almost 65% of his hits since coming back are grounders and pop-ups (63.1%). His pull-rate is basically the lowest of his career. He's hitting a lot soft (22% - usually around 16%) and nothing hard (24.4% - usually around 34%). He's a worse version of the player that the Nats saw back in 2011. He's not helping the team being out there.
Of course sitting Werth is easier said than done (espeically with Bryce nursing a sore knee and Span not close to returning). You could just play Robinson for him. That would be an improvement, although an admittedly minor one. You could scour the waiver wire for a replacement. De Aza? Byrd? Again - minor improvements probably (actually Marlon would be a nice move) but minor improvements are still improvements.
But it's not just the available options that get in the way. There is the "Werth-iness" that is problematic. Ian might be the internal leader on the team, but Werth is the external face. For all the talk about Bryce, Werth is the one with the Chia pet and the troll doll and the 21 million dollar contract. Should you sit that? Yes. Can you? Maybe not, depending on the guys in charge.
Werth also has (in pure theory - like the one that proves 1+1=2) the best possibility of a big impact. He was very good the last two years, great even. If he does "get it" he'll be better than anything they can bring in.
So there is a lot working for playing Werth while the stats scream sit him. Is there a compromise? Yes. Move him down in the order. Bat him 7th. 8th. If you truly think he needs to work his way back and that's all it shouldn't matter if he's batting 4th or 5th or 9th. It'll happen. In the meantime if it's not happening he's not stranding runners again and again.