The veteran National's postseason availability will hinge on how he plays and his hamstring responds over the final week-plus.
Doug Fister goes for his 15th win as the Nationals look to stay on a roll.
Rafael Soriano is confident he'll be ready for the playoffs.
Everyone is in the starting lineup against the Marlins as the Nationals aim to lock up the NL's top seed.
Who would the Nationals match up well against in the first round of the playoffs?
If the Nationals win a game, the coach who brought up the lineup card has to do it again. Matt Williams has the best record.
The left-hander has a 2.79 ERA over his past six starts and is pitching perhaps the best he has all season.
Zimmerman went 1 for 7 in an intrasquad game and is expected to play seven innings in left field on Friday.
The Nationals will start their final road series of the year behind Gio Gonzalez.
Adam LaRoche is out of the lineup so that he can get extra rest for his old back injury.