Young Nats who might get a closer look the rest of the season

If the Nationals truly have waved the white flag on 2018 - whether they have depends on your interpretation of Tuesday's trades and subsequent statements made by Mark Lerner, Mike Rizzo and Davey Martinez - then their focus for the remaining 5 1/2 weeks of the season is going to have to shift at least somewhat toward preparing for 2019.

What, though, does that mean from a practical standpoint? What players might we see the rest of the way who might not otherwise have received this kind of opportunity?

First and foremost, the Nationals have a chance to look at some different second base options after Daniel Murphy was traded to the Cubs. Wilmer Difo got the start Tuesday night against the Phillies, hit the go-ahead homer and will probably continue to get a good number of starts through the rest of the season.

Is there much left for the Nats to learn about the 26-year-old? Difo has now played in 286 big league games, amassing 782 plate appearances, during which time he has hit .257 with a .312 on-base percentage. He's hardly a finished product at the plate, but there's enough of a track record there for the Nationals to have an idea what they've got in him.

In the field, Difo has established his credentials. He's a good, though probably not great, defender. He was outstanding at shortstop in 2017, with 14 Defensive Runs Saved, the third-highest total in the majors at the position even though he had considerably less playing time than others. The bulk of his time this year has come at second base, where he ranks tied for ninth in the majors with four Defensive Runs Saved.

If you're wondering about prospects waiting in the wings in the minors, the Nationals do have a potentially good one in Carter Kieboom. The organization's 2016 first-round pick (and younger brother of current big league catcher Spencer) has hit a combined .287 with 16 homers, a .365 on-base percentage and .826 OPS between Single-A Potomac and Double-A Harrisburg.

Kieboom clearly is in the Nationals' future plans, the question is how soon they expect him to make an impact. And where he fits into the infield plan, though Rizzo made it clear Tuesday it won't be at second base in 2018.

"Carter's never played second base in his professional career, so it would be unfair for me to do that at the big league level," the GM said. "He's progressed beautifully to where he's at. He's going to be in the Arizona Fall League as one of our premier players in the fall league. He's had a lot on his plate. He's had a terrific career with us as short as it has been. His needle is facing north, and we don't want to sidetrack that."

The Nationals don't really need to look at anyone else at first base in the wake of Matt Adams' trade to St. Louis. Ryan Zimmerman had already reassumed near-everyday duties there, and they also have veteran Mark Reynolds seeking at-bats.

One interesting scenario, though, would have Bryce Harper getting a look at first base for the first time. Harper occasionally takes grounders there pregame, and he actually appeared there for one batter as part of a desperation five-man infield alignment last month.

If the Nats gave Harper a few chance to play first base on days when Zimmerman sits, an outfield spot would open. And that spot could go to robleVictor Robles, the franchise's top prospect who has not spent a day in the major leagues yet this season but surely is coming sometime soon.

Robles, who dazzled last September and even made the postseason roster at 20, missed three months this season after hyperextending his left elbow. Healthy now, he's hitting .254 with a .365 on-base percentage but only one homer in 38 games for Syracuse.

The Nationals have a decision to make on Robles this winter. If Harper leaves as a free agent, Robles almost certainly becomes the starting center fielder in 2019. If Harper stays, Robles could be extraneous and thus a prime trade chip. The more the club (and other interested clubs) can evaluate him the rest of this season, the better.

The Nats didn't move any pitchers Tuesday, but that doesn't mean they aren't also facing questions on the mound for the season's final 5 1/2 weeks. Both Erick Fedde and Joe Ross are currently on rehab assignments and are expected to return from injuries (shoulder inflammation for Fedde, Tommy John surgery for Ross) to pitch in Washington in September.

Given their rotation questions heading into 2019 - only Max Scherzer, Stephen Strasburg and Tanner Roark are under contract - the Nationals probably want to see where Fedde and Ross stand and determine whether one or both merit a spot in the opening day rotation.