Commenter BJD1207 brought up a good point. Not only is the LHB on the bench limited, but the LHB on the Nats isn't all that great either. If Bryce Harper gets injured, what happens? Sure the Nats can still hit lefites but what about the team versus right-handed pitching?
The good news is that righties rarely have the extreme splits you can see with lefties. They've seen RHP all their lives and are accustomed to it, so while they can't hit it as well as LHP, they generally hit it at a level only slightly below. Of the right-handed batting starting players in the Nats lineup, only Rendon has shown any great split and for all we could know that could be a fluke. I went ahead and estimated the OPSs of the Nats expected line-up (Span, Ian, Zimm, Werth, Bryce, Ramos, LaRoche, Rendon) vs either hand and came up with this.
vs R : 740, 800, 800, 820, 930, 780, 820, 700
vs L : 650, 820, 850, 1000, 688, 770, 620, 830
This is real rough but factor in pitching, some injury replacement games, some pinch hitting, and what you get is an offense that should be one of the best in the league vs right-handed pitching, and should be above average versus lefites. That doesn't exactly make sense on the surface given a lineup with 5 righties and 3 lefties, but dig a bit deeper and you'll see that the Nats' lefties (Span, LaRoche, Bryce) suffer some major splits, while the right handed bats don't see that. Against a left-handed pitcher, essentially the middle of the line-up has to carry the team (and it can to some degree). Against a right-handed pitcher, there really isn't easy stretch outside of maybe the 8-9-1 trio.
What happens if the Nats' lineup loses Bryce for an extended time? Against lefties not much, presuming Hairston or another right handed bat takes his place. It's doubtful they'd do worse than the still adjusting Bryce. Against a righty though you'd likely see McLouth and his .740 ish OPS replacing Bryce's .930. That's a big enough deal to drop the Nats lineup from "possibly the best" to simply "above average"
It's not surprising. With Bryce in the line-up the Nats are likely one of the best in the league. Without Bryce in the lineup they are still good but they aren't likely to crack the Top 3. Good enough for a playoff spot with the pitching they have, but good enough for a divison title? Depends.
Of course this is not really any different than what the Nats have at any other position. If Zimm or Rendon or Desmond goes down and Espinosa or Frandsen get more playing time - those are big drops in OPS. Ramos goes down? Drop. Werth, even with platooning Hairston/McLouth? Drop. The only injuries that the Nats might be able to weather offensively with no significant drops is catcher (maybe), 1st base (with a Hairston/McLouth platoon some how worked into the lineup), or centerfield (offense might actually improve but defense could be scary bad). This isn't really a flaw in the system though. It's the reality. Your bench is not capable of starting. That's why they are the bench. The only thing that elevates the Bryce thing above all these other injuries (ignoring future implications) is that it would leave the bench with 0 reliable lefty bats. So it is a slightly worse situation given how the team was built.
Take away lesson? Pray for health.
Season Preview and predictions on Monday!