WASHINGTON -- Infielder Chad Tracy has yet to a start a game during the regular season, but that will change on Saturday, when he starts at first base against the Marlins.

The move means Adam LaRoche will get the day off.

Manager Davey Johnson's original plan was to give Ryan Zimmerman the day off Saturday, because he was off to a slow start, but Zimmerman went 4-for-13 (.308) with a home run and three RBIs in his last three games against the Astros.

Tracy, a valuable left-handed bat off the bench, entered Friday's series opener 2-for-10 [.200] with three RBIs.

Johnson to vary left fielders in Morse's absence

WASHINGTON -- Nationals manager Davey Johnson acknowledged on Friday afternoon that he was "wishy washy" when it comes to the left-field situation, meaning he didn't have a set plan at the position.

Xavier Nady and Roger Bernadina are set to platoon in left field whenever there is an opposing left-hander on the mound, and Mark DeRosa will play right field, while Jayson Werth will be switched to center field.

Bernadina, DeRosa, and Nady haven't been productive up to this point. All three players are hitting below .210 and have yet to hit a home run. With Michael Morse expected to be out of action for at least another month, the Nationals need production from those three players.

"I want to simplify the equation. I'm going to simplify it. It will be easier for the guys," Johnson said. "There will be plenty of spots, key spots [for DeRosa] to help us win the ballgame. He is the least of my worries. I know what he can do. He played for me before. I know what he can do. I know less about Bernadina and Nady. I would like to see them get going. I know DeRosa is going to be there."

Worth noting

• Friday was Brad Lidge's turn to pitch the ninth inning, but Nats manager Davey Johnson decided to go with the hot hand, calling on Henry Rodriguez to close out the 2-0 victory over the Marlins. It was Rodriguez's fourth save of the season.

• Steve Lombardozzi received his Minor League Gold Glove Award on Friday. While playing for Double-A Harrisburg and Triple-A Syracuse, Lombardozzi made a combined two errors in 539 chances in 2011.