Stanton has a bruised left shoulder, and he has missed five games.
"He took batting practice, and we're just going to wait to see the way it responds," manager Mike Redmond said. "He hasn't done anything in five days. We'll see how it feels throughout the day, and tomorrow, and we'll go from there."
Stanton last played April 10, and he took batting practice last Friday before being scratched about 30 minutes before the Marlins faced the Phillies.
An MRI taken on Saturday revealed a bruise, and Stanton has felt a pinch when raising his arm. But on Tuesday, he was considerably better, and tested the shoulder by swinging the bat.
Before being cleared to play, the team is waiting to see how Stanton's shoulder responds the day after doing baseball-related activities.
"He said it felt good," Redmond said. "It felt a lot better. That's encouraging. I'm hoping that he shows up tomorrow and it feels even better. That will be a really encouraging sign."
Although Stanton is off to a slow start, hitting .167 with no homers or RBIs in 30 at-bats, Stanton remains one of the most feared hitters in the game.
Miami has struggled to manufacture much offense, and being without their biggest threat has been tough.
The Marlins wrap up their nine-game homestand on Wednesday, and it is questionable if Stanton will be ready for the series finale with the Nationals.
Perhaps a more realistic return is when the team opens a four-game set at Cincinnati on Thursday.
"We want to make sure that he's right, and that it doesn't still hurt him," Redmond said. "We don't want to push him. We want to make sure everything feels right with him before we do that."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter