Zach Walters (right) after his first major league home run in April. (AP Photo/Lynne Sladky)

While Ryan Zimmerman rests his significant hamstring strain and the Nationals await another evaluation of it, there is an obvious void in the lineup. Anthony Rendon shifted back to third base, and Danny Espinosa was expected to man second base in the meantime. But against a right-handed starter on Friday in Cincinnati, Nationals Manager Matt Williams instead turned to rookie switch-hitting infielder Zach Walters at second.

The reason? Most of Walters’s power this season has come from the left side of the plate — 12 of his 15 home runs at Class AAA Syracuse were left-handed and he had a .963 on-base-plus-slugging percentage against right-handers. Espinosa, meanwhile, has a .556 OPS from the same side this season. Williams stopped short of using the word “platoon,” but he admitted he was mixing and matching at second base.

“With Zim’s loss, we’re looking for a little bit of offense,” Williams said. Walters has “been swinging well. It’s a small ballpark [in Cincinnati], and with him being able to drive a ball out here, he’s going to get a start eventually over there.”

Walters is a relative novice at second base. He worked out there during spring training and in the minors played in games there for the first time since 2011. At Syracuse this season, Walters has played 27 games at second base, as many as he has at third base and more than his natural position at shortstop. When Walters was sent back down to Syracuse in late May, he played more second base and he said he grew more comfortable.

Friday will be Walters’s major league debut at second base. He has started three games in the majors this season at three different positions (left field, third base and now second). How often Walters plays second base as part of a platoon with Espinosa will depend on how he plays. With the non-waiver trade deadline less than a week away, the Nationals could always add an infielder via a swap with another team.

“This is as good a time as any since [Walters has] been playing all the time,” Williams said. “His timing will be good. We’ll see what he can do. The reports that everybody reported is that he feels comfortable out [at second] and has been playing well.”

Williams said Espinosa could still appear in Friday’s game as a late-game defensive replacement if the Nationals have a lead, or perhaps as a pinch hitter against a left-handed pitcher. Kevin Frandsen can also play second base.

“We’ll see how it goes” with Walters,” Williams said. “We’re back in that situation where we’ve got a guy down and we kind of have to mix and match. [Friday] is as good a night as any.”

As for Zimmerman, Williams said the infielder is still resting his injured leg muscle. Williams said the Nationals didn’t have a grade for the hamstring strain because the team is waiting to see how Zimmerman responds to the inactivity. Williams suggested Zimmerman would be shut down completely for at least two weeks. Zimmerman is expected to see a team doctor on Monday, Williams said.

“It’s really early,” Williams said. “His plan right now is to rest and not do anything. … For the next week or so it’s going to just be really nothing that he can do. If they start digging in there, somebody starts massaging it, it doesn’t allow it to heal as it should. He’ll just be shut down for a while and go with that.”