Five keys to the Nats turning their season around

The challenge facing the Nationals over the final 66 games of the season is significant. They not only have to make up a 5 1/2-game deficit to win their third consecutive National League East title, they have to leapfrog over two division rivals to do it. Which means there's little margin for error, beginning with this weekend's three-game series against the second-place Braves.

Thing is, Davey Martinez has been a part of something like this before. Only one year ago.

The Cubs came out of the 2017 All-Star break a surprising 43-45. They trailed the Brewers by 5 1/2 games in the NL Central and were tied with the Cardinals. What happened next? They won their first six games out of the break, took over first place two weeks later, went 49-25 and never looked back en route to a division crown (and matchup with the Nationals in the NL Division Series).

"There's some similarities," Martinez said as the first half wrapped up in New York on Sunday. "Our focus now is to have these four days off, recoup and be ready to come back Friday and start fresh and start winning consistently. That's the big thing."

How do they accomplish that? Here are five key storylines for the second half of the Nationals' season ...

CAN THE ROTATION LEAD THE WAY AGAIN?
At the end of play on June 7, Nationals starters owned a collective 2.89 ERA, tops in the NL and second only to the Astros in the majors. Since then, they've posted a 6.34 ERA, worst in the majors by leaps and bounds.

What happened between June 7 and June 8 that changed everything? (Besides the Capitals winning the Stanley Cup, of course.) Stephen Strasburg came out of a start after two innings with right shoulder inflammation. The Nats rotation hasn't been the same since.

The good news: Strasburg returns tonight after two successful rehab starts. The Nats desperately need him to return to the form he displayed late last season after his brief DL stint and once again pair up with Max Scherzer to form one of the most formidable 1-2 pitching punches in baseball.

But even that's not going to be enough. The Nationals' No. 3 and No. 4 starters have to step it up, as well. Gio Gonzalez and Tanner Roark have done it before. They're going to need to do it again, with No. 5 starter Jeremy Hellickson merely continuing what he has done to date this season.

This team for years has been built to win on the strength of its dominant rotation. If it's going to win again in 2018, that group is going to have to lead the way as it has before.

CAN HARPER RESURRECT HIS SEASON?
There are plenty of reasons for the Nationals' offensive struggles this season, but rather than nitpick over all the little things, let's step back and look at the biggest thing: Bryce Harper hasn't been himself, at least not since a dominant April. Since May 5, he's hitting .190/.317/.394 and striking out in 30 percent of his plate appearances.

That's a problem. It's kind of hard for a lineup to consistently be productive when the most important member of that lineup is struggling to that extent for that long a period.

So even though the Nationals would benefit from improved performances from several others, especially in the department of manufacturing runs, the single best way for this lineup to become a potent force again is for the best hitter in that lineup to start hitting like the best hitter in that lineup again.

Was Monday night's jaw-dropping performance in the Home Run Derby a sign of good things to come for Harper, or was that a mere blip before he returns to the hitter we've seen the last two-plus months? We're about to find out, and the Nats season might well rest on the answer.

WILL MURPHY, EATON AND ZIMMERMAN RETURN TO PRE-INJURY FORM?
Harper, of course, can't do it alone. He does need help. And that's where Daniel Murphy, Adam Eaton and Ryan Zimmerman come in. All missed considerable time due to injury during the season's first half. All are now back healthy. (Zimmerman is expected to be activated before tonight's game.)

But can all three return to the form they displayed before they got hurt? Murphy finally started to show signs in the last week before the break, going 8-for-15 with four walks to raise his batting average from .194 to .253. The power still isn't there, but he seems to be moving in the right direction.

Eaton has produced whenever he's been on the field - did you know in 60 games with the Nationals the last two seasons he has hit .312/.393/.434? - but he has yet to prove he can stay on the field for the long haul. The Nats really need him to play enough the rest of the way to amass 250 or more plate appearances, setting the table for this lineup.

Zimmerman is the biggest question mark of the bunch, because he wasn't hitting before he strained his right oblique muscle in May. This season has been a nightmare for the veteran first baseman on the heels of his dramatic comeback season in 2017. He hit well on his rehab assignment, though, going 4-for-9 with a homer and two walks, so perhaps he can carry that over into his big league at-bats now. If he can't, the following storyline becomes even more significant ...

HOW WILL MARTINEZ HANDLE ROLES DOWN THE STRETCH?
Davey Martinez admittedly has been learning on the job, as most rookie managers do. The problem is that most rookie managers don't take over clubs with this much pressure on itself to win now. So the time for rookie mistakes is over, and Martinez is going to have to be better the rest of the way, just as his players have to be better.

The ways he can do that are to make the right decisions with regard to playing time, lineup placement and bullpen usage.

Playing time: Is Zimmerman going to be the everyday first baseman, relegating Matt Adams to the bench? What if it becomes clear early on that Adams is the better option? Is Martinez willing to make that tough decision?

Lineup placement: Is Harper going to continue to bat third or fourth every night, even if he's struggling? If Martinez has better options (Adams, Juan Soto, Anthony Rendon) to bat in those prime spots, is he willing to bump Harper down a few notches? Or even force him to take more days off so Michael A. Taylor can play?

Bullpen usage: Ryan Madson and Brandon Kintzler each went on the DL after some heavy usage. Kelvin Herrera hasn't looked like himself since his acquisition. Sean Doolittle is on the DL now, though it doesn't appear to be serious and it wasn't the result of overuse. Regardless, Martinez needs to find a late-inning formula that both works and protects everyone's arms so they're all available down the stretch.

WILL THEY MAKE BIG, SMALL OR NO MOVES AT THE TRADE DEADLINE?
There's only 11 days to go until the July 31 trade deadline, which isn't much time for Mike Rizzo to decide what exactly needs to be done to better position this team for the remainder of the pennant race (and possibly beyond).

Rizzo already bolstered the bullpen with the trade for Herrera, but there are more holes yet to fill. We know catcher is an area of significant need, though where does he turn with J.T. Realmuto too expensive and Wilson Ramos likely on the DL into August?

What about the rotation? Even if everyone returns to form, is that group as currently constructed good enough to get the job done in crunch time? There's been a line of reasoning since the winter that this team really needs a stronger No. 3 starter to pitch behind Scherzer and Strasburg. Does Rizzo have a bold move in him to acquire one?

Or is the general manager more likely to make small tweaks to the roster, adding another bench player or lefty reliever to the mix? Would that be enough? We just saw the already-loaded Dodgers add Manny Machado as a rental acquisition. Would the Nationals be willing to do something that bold in a go-for-broke move?