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8/31/2013 8:30 P.M. ET

Nats give Rendon a break, start Lombo at second

WASHINGTON -- Steve Lombardozzi started at second base for the second time in four games on Saturday, a move that manager Davey Johnson explained as an effort to give Anthony Rendon some more time off.

Rendon has played in 114 games between Double-A Harrisburg, Triple-A Syracuse and the Nationals this season. In 2012, his first year of professional baseball, he only played 43 games after returning from surgery on his right ankle. Johnson said that some of his coaches occasionally tell him to give Rendon a break.

"Some of us think that he should be on an innings limit like some of the pitchers, because this is the first season he's played over 50 games," Johnson said. "So that's all it is."

Lombardozzi's recent success also factored into the decision. He hit the first pinch-hit home run of his career on Friday night and is hitting .329 in his past 36 games entering Saturday. After ending a homerless drought on Aug. 22, he has now gone yard twice in his past eight games.

"Lombo's got this power surge going," Johnson said, "so I'm going to take advantage of it."

Davey thinks Harper's knee could still be an issue

WASHINGTON -- When Bryce Harper didn't run out a routine ground ball in the eighth inning on Friday night, bench coach Randy Knorr questioned the All-Star's effort on some plays this season. Before Saturday's game, manager Davey Johnson agreed that Harper should have sprinted down the line.

"My opinion is you take nothing for granted," Johnson said. "You hit a ground ball, the guy could boot it. You run. Anytime you quit going hard, it's a losing attitude. With him, I'm in between knowing if he's babying his knee, because he's usually 100 percent in. But I'll talk to him."

After missing the entire month of June with bursitis in his left knee, Harper has started 50 of the Nationals' 54 games since, including Saturday. Harper has not had any major setbacks with the knee, but Johnson believes that the injury might still be hampering the 20-year-old.

"I think it's still an issue. I think it's probably there," Johnson said. "He can probably play with it, but if he headfirst slides or dives in the outfield, it's probably going to flare up. But hopefully, he'll get through the season."

When asked if Harper should consider offseason surgery to have the bursa sac in his knee removed, Johnson said that decision would have to be made by Harper and team doctor Wiemi Douoguih.

"That was talked about a while back," Johnson said. "That's definitely an option."

Worth noting

Johnson was dehydrated Friday night and left the dugout in the fourth inning because he was feeling light-headed. Johnson said that he felt much better on Saturday.

"I pinch-hit for myself," he said. "But after a good night's sleep, I feel great."

Tom Schad is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.