Stanton had doctors appointments scheduled for Tuesday, after which manager Mike Redmond said the team will have a better idea whether the Marlins have any hope of getting their National League MVP candidate back before the season ends.
"We'll have an official statement [Wednesday], but it's probably not looking good for him," Redmond told MLB.com.
Stanton, who leads the NL in home runs (37) and is second in RBIs (105), was hit in the face by an 88 mph pitch from Milwaukee Brewers starter Mike Fiers on Thursday night and sustained facial fractures and dental damage.
"He's feeling much better, and you can tell in just a short amount of time you can tell how much better everything looks, the swelling has gone down," Redmond said. "That's why he's going through the evaluations and the tests to see where he's at."
On Monday night, the team hung Stanton's jersey in its dugout before getting a 6-5 road win over the New York Mets.
"I would want nothing more than to have him step into that box before the season's over, just for him to have that comfort level of knowing that he got back into that box and didn't have for his last memory of the 2014 season of being get hit in the mouth," Redmond said. "But we're not sure that's a reality."
Information from The Associated Press was used in this report.