Stanton hopes to return to the big league club on Aug. 10 to face the Los Angeles Dodgers during the Marlins' next homestand.
"It's not fun to just sit there helpless," Stanton said. "You still pick up some things, learn from the down times we are going through, that's all you can do. I'm eager to get back, I'll be ready."
Stanton, a 22-year old right fielder selected this year for his first All-Star team, is hitting .284 with 19 homers and 50 RBIs in 80 games. He has not played since July 7 and was expected to miss 4-6 weeks after undergoing arthroscopic surgery on July 9.
Marlins left fielder Logan Morrison was placed on the 15-day disabled list before Sunday's game against San Diego because of right knee inflammation.
"I've battled it the whole year, grinding it out, and obviously I wasn't doing anything to help the team win so I had to make a decision," Morrison said. "I'll try to rest it and not do (surgery). If that doesn't work out, obviously surgery is the next step."
Morrison is hitless in his last 16 at-bats and is batting .230 with 11 homers and 36 RBIs.
Information from The Associated Press was used in this report.