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5/31/2014 1:30 P.M. ET

Zimmerman to get start in left at Class A Potomac

WASHINGTON -- The Ryan Zimmerman left-field experiment officially begins Saturday night.

No, not on the Major League level with the Nationals, but at Class A Potomac, where Washington's everyday third baseman is serving a rehab assignment. Zimmerman, on the 15-day disabled list since April 13 with a right thumb fracture, got four at-bats as the designated hitter with Potomac on Friday night. Now comes the next step: putting the glove on.

"The plan is he'll play five innings tonight of defense," Nationals manager Matt Williams said before Saturday's home game vs. the Rangers.

Not just defense, but at a position he's never played on the professional level.

"He's ready," Williams said. "He's done a lot of work out there. You still have to do it though. He's ready to go."

The shift to the outfield with Washington is not a lock, but the Nationals and Zimmerman are prepping for the day when there might not be another option. Shoulder injuries have hurt Zimmerman's ability to throw from the hot corner. He spent recent days in the outfield with Washington's coaching staff during pregame sessions.

"There is no way to get true, real line-drive balls. Even in batting practice, you can't really simulate it," Williams said. "That's the difference, balls coming off the bat differently, certainly with more authority."

As for how Zimmerman did with the bat in his hand, he was 0-for-3 with a sacrifice fly on Friday.

"He felt good. He wanted another [at-bat]," Williams said. "Four is good for one day. Tonight, he'll play five full innings regardless of where they're at in the lineup. I'm sure we'll have some call this evening saying, 'Can I have another at-bat in the sixth?'"

Nats get ready for first matchup with Darvish

WASHINGTON -- Rangers starter Yu Darvish is a true staff ace, one of the baseball's best pitchers. The Nationals will get their first look at the sterling right-hander in Sunday's series finale. That makes for a challenging matchup, one that could psych out a batter or nine. From Nationals manager Matt Williams' perspective, the matchup for Washington's lineup isn't really against Darvish.

"Once the pitcher releases the ball, it's not about you and the pitcher anymore," the former slugging third baseman said. "It's about you and the ball. Always have to remember that. [Batters] have true authority as soon as it's released. We can choose to whether swing or not and what to do with that pitch."

Darvish (4-2, 2.35 ERA) was scratched from his previous start with neck stiffness. Over his three previous outings, the 27-year-old allowed four runs and 13 hits while striking out 29 over 23 2/3 innings.

"True aces have really good pitches, and Darvish is one of the best at it," Williams said. "[He has] a number of different pitches moving in a number of different ways and a 97-mph fastball when he wants it. But we are in control at the plate as soon as he releases it.

"No different than any other day. If you put too much emphasis on it … you tend to tense up, try to do too much and probably play into his hand a little bit."

Tanner Roark (3-3, 3.47) is slated to start for the Nationals on Sunday.

Worth noting

• Including Friday's 9-2 series opening win over the Rangers, the Nationals are 22-2 when scoring four or more runs. On the other hand, Washington sports a 4-25 record when three or fewer runners cross home plate.

• Washington's relievers lead the Majors in bullpen ERA (2.21). Drew Storen and Blake Treinen tossed three scoreless innings in relief of Stephen Strasburg on Friday night. Entering Saturday, Storen had not allowed a run in eight consecutive appearances dating back to May 13.

• With Saturday's 12:05 p.m. start time, Jose Lobaton started at catcher in place of Wilson Ramos. Lobaton entered the game batting .227 (20-for-88) with one home run and eight RBIs in May, and he hit a two-run homer in the second inning Saturday.

Ben Standig is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.