Stanton, 22, was hitting .284 with 19 home runs and 50 runs batted in over 80 games before he was placed on the 15-day disabled list a month ago. He underwent surgery to remove "loose bodies" from his right knee.
He will be available for Tuesday's game in New York against the Mets.
Stanton is in his third season with the Marlins. He's a career .266 hitter with 75 home runs and 196 RBI. He was selected to the National League All-Star team this year.
Miami placed infielder Donnie Murphy on the 15-day disabled list to make room on the active roster for Stanton. Murphy, 29, has a left hamstring strain. He's hitting .194 with three home runs in 33 games this season.