I like the All-Star break where it is. It separates the baseball season not into exact halves but into "don't worry there's plenty of time" and "uh oh, you need to start winning like, now" time periods. It starts with two weeks of "do we need to deal for someone now or not" where every at bat or start from a marginal player is picked apart. After that it's August and the stretch run begins getting increasingly tense as the number of games left gets smaller and smaller.
If the All-Star game were half-way through the season, you'd come out of it with a full 3 months left to the season. Even though it's only about 2 extra weeks of baseball we're talking about, you'd lose that a sense of immediate urgency.
Anyway where do the Nats stand now? Depends on Zimmermann.
If Zimmermann is not healthy then a starter becomes an obvious priority. The Nats wouldn't actually NEED a starter at that point to continue to contend for a play-off spot with Stras, Fister, and Gio slotted 1-3. But not getting one would leave their playoff chances to the mercies of fate. A ZNN injury would kill what little depth the Nats have (no one in AAA is pitching particularly well recently) so one would think one more pitching injury would probably cripple them.
But all signs are that Zimmerman are healthy so let's leave the SP discussion out for a few days. What other areas of improvement do the Nats have? Well whether they start Span or they start Espinosa they have a spot in their lineup that could be improved. Span is the better offensive player so the question really is can you find a OF or 2B that will improve on Span's bat by alot. Two remote possibilities (Stanton and Daniel Murphy) are non-starters as those are intradivisional rivals who expect to challenge the Nats in the next couple of years. They aren't trading good players to the Nats.
As far as the OF is concerned there is no one straight up good enough to be a slam-dunk replacement of Span. A couple guys can hit, like Willingham, Byrd, or Alex Rios, but they are more corner outfielders, which means you'd have to bet on Bryce to carry CF with questionable talent at the corner spots. I don't feel good about that unless the bat you are bringing in is a game changer and those guys aren't.
Oddly 2b gives you a few more options, along with Murphy, Chase Utley would be a great fit, and the Phillies would be waving a white flag to the next couple years by dealing him. But it's a tough trade to see happen unless the Nats wow the Phillies and the Nats aren't the type of dealer that gives up a lot in prospects. Plus, Chase has no interest in being traded.
So the only starter type-deal that would make sense for the Nats is one for Ben Zobrist who can play 2B and OF. This would be ideal. Zobrist is patient (his OBP would immediately be 3rd on the team), hits at the top of the line-up (could take that spot from the ill-suited Span), and plays good defense. He could play 2B float most of the time allowing Rendon to play 3B and Zimmerman to play OF and if that isn't working out he could play OF with Bryce shifting to CF without missing a beat. Plus, the Rays and Nats have trade history together with the Karns/Lobaton deal happening just this offseason. However, Zobrist is a starter and will cost a lot if he's up for trade. The Nats have yet shown they are ever going to be "all in" and I don't think they'll start with a mid-season trade.
So that leaves back-ups. The Nats could use an IF replacement that can hit and a late inning defensive replacement in the OF or 1B.
The former is nigh-impossible to get. Maybe a Luis Valbuena or a Sean Rodriguez? They would provide pop that Frandsen does not, while admittedly providing the low average Frandsen does give. In the minors if you don't like Zach Walters (and I don't - I think he's useful only in HR or nothing scenarios) then the cupboard is bare.
As far as the OF would go, there isn't an obvious defensive replacement out there. They could probably pick up a Cameron Maybin for cheap. Gerardo Parra or Ryan Sweeney... maybe Emilio Bonaficio (not my choice)? Of course this would only be worth it if the manager would pull Werth or Bryce late in the game, and I don't know if Matt Williams is that kind of thinker. A more interesting solution, if the Nats weren't inclined to worry about "starting clocks", would be bringing up Michael Taylor. He looks good enough at the plate in AA to maybe hang in the majors. True at first he'd probably be a lot like Walters but we're talking D not O for the OF, and Taylor is supposedly one of the best in the minors.
That's about where the Nats stand now. They are waiting on ZNN to see if he's really ok like they say. If so they could maybe make a big splash and grab a Zobrist, but more likey (for a number of reasons) will go small. The question is does that mean grabbing a Valbuena or Rodriguez and calling up Taylor to better round out the bench? Or does that mean doing nothing because nothing is easier, cheaper and hey- they aren't pressed to do something right now? We'll see.
Either way the likely move is playing at the margins for a team that should make their push in July to the top of the heap.