Victor Robles was set to make his first career start as a leadoff hitter before Sunday’s postponement. (John McDonnell/The Washington Post)

There seem to be few bounds to what Victor Robles can do on a baseball field, with his blazing speed on the base paths, legs that take him all around the outfield and lightning-quick bat teasing power that could blossom when his elbow fully heals.

It all gives Nationals Manager Dave Martinez a chance to experiment with the 21-year-old prospect, who is playing in the majors for the second straight September and coming upon increased opportunity this weekend. Robles started both games of the Nationals’ doubleheader sweep of the Chicago Cubs on Saturday, playing left field and hitting sixth in the first one and playing center and hitting fifth in the second. Then he was set to make his first career start as a leadoff hitter on Sunday before rain washed away the Nationals’ series finale with the Cubs.

The postponement of Sunday’s game came at 4:35 p.m., roughly three hours after it was supposed to start at Nationals Park. It will now be played this Thursday at 4:05 p.m., and the Nationals will need to return to Washington between trips to Philadelphia and Atlanta. The Cubs will come back in the middle of a six-game homestand. Nationals right-hander Erick Fedde, who was supposed to start Sunday, will now go against the Philadelphia Phillies on Monday. That bumps every pitcher back a day, and the Nationals will round out the Phillies series with Tanner Roark on Tuesday and Stephen Strasburg on Wednesday.

And even though the weather delayed Robles’s debut atop the Nationals’ lineup, it is more than likely that he will get another crack at that soon.

“I’m still trying to figure it out. The sky is the limit with him,” Martinez said Sunday of whether he envisions Robles hitting leadoff in years to come. “He’s got potentially five tools. We’ve seen everything he can do, and we’ll see where he ends up. But if he can get on base, I mean it would be nice to have him up there.”

Just the chance of those five tools — hitting for power, hitting for average, fielding, arm strength, speed — makes Robles the Nationals’ most intriguing prospect and, by default, one of the brightest spots of this dreary September. But it is that speed, already apparent in everything he does, that could make him an electric leadoff hitter. Across this season and last, most of his starts have come as the fifth or sixth hitter in the order, and he has a .206 average in just 39 plate appearances.

Now he can show where he fits in the Nationals’ future, a question not limited to any number of answers.

“Just be himself,” Martinez said of what he wants to see out of Robles in the leadoff spot. “Work good counts, just get on base and have fun.”

When Robles joined the Nationals at the start of this week, Martinez was adamant that he would find ways to play him. That is not an easy task given the Nationals’ crowded outfield, with 19-year-old Juan Soto chasing the National League Rookie of the Year award in left, Bryce Harper carved in at center and veteran Adam Eaton hitting well as an everyday right fielder. Robles came off the bench in his first three games, Friday’s game was postponed due to rain, and Martinez tried to use Robles instead of Eaton for three straight games.

That moves Harper to right field, a more natural spot for him, and leaves Robles to roam in left or center depending on who else is in the lineup. Martinez said Sunday that there are no injury concerns with Eaton and that this damp weekend has been a chance to get the scrappy 29-year-old a couple of days off. That makes it the second time in three games that Martinez constructs an outfield of Soto, Robles and Harper, a rare blend of power, speed and patience that may be fleeting with Harper’s impending free agency.

“He’s a veteran guy, been playing his tail off. This weather is not … it takes him a while to get loose,” Martinez said of Eaton. “I told him [Saturday] he was going to play [on Sunday], and I came in this morning and I decided, you know what? Let it be as is. We got some young kids up here, and I want to see them play, too. He’s good; he’s all good. He’s going to play all next week.”

Eaton is the Nationals’ usual leadoff hitter, so another day of rest almost opened that spot for Robles on Sunday. Had it not been for an early season elbow injury, it is likely that Robles would have come up this spring when the Nationals needed to patch a few holes. The injury could have sapped Robles of some power — he hit just two home runs in the minor leagues this season — but Martinez thinks that will return when the winter offers more time to heal. Martinez sees him smacking 50 to 60 doubles in the future, maybe leading the league in extra-base hits, playing sound defense and hitting his share of home runs, too. That’s the manager’s vision as of Sunday. That, of course, is subject to change, too.

The injury also opened an opportunity for Soto, who sprinted with it, hit .298 with 16 home runs and left Robles to make the most of scattered starts and at-bats at this month. Those will keep coming for Robles, as often as Martinez can get them to him, and each moment will show what he can do. But if early glimpses are any indication of what the Nationals can expect and hope for, the easier question may be what it is that he can’t.

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