Stanton broke the hamate bone in his left hand on June 26, and two days later underwent surgery, but his wrist still isn't at full strength.
"Just wrist weakness," Stanton said. "It's not the actual surgical part. In terms of impact on my incision area, it's fine. It's the weakness in my wrist turning over. It's a little different."
With Stanton, right now is basically a matter of man vs. machine.
Stanton is testing the strength of his hand and wrist with 95-mph pitches.
"When I can hit off the machine for probably five to seven days in a row without pain," Stanton said when asked when he'd know he's ready. "That's game simulated and would be like playing every day for my wrist and hand."
Building the strength has been a process.
"It's much stronger," Stanton said. "We're getting there. Slowly, but we're getting there."
Stanton, who has appeared in 74 games, has 27 home runs and 67 RBIs.
One adjustment he is making is with his bat. He is now using a Marucci bat, which is 34 inches, 32 ounces, but it has a narrower handle than before.
The handle is designed to make it easier for him to turn his wrists.
"I need 100 percent of my wrist," Stanton said. "I can't go up there against 95 miles per hour and just give 75, 60 percent of my wrist to turn that all over."
Manager Dan Jennings is optimistic that in September the Marlins will have Stanton and right-hander Jose Fernandez (right biceps strain) in the lineup.
"We've had many talks amongst our staff about we'd love to see the last month of the season we have everyone back and healthy," Jennings said.
Fernandez is throwing off flat ground.
The Marlins also have outfielder Christian Yelich (bruised left knee) on the disabled list.
Yelich is doing baseball activities, but still is dealing with swelling in the knee, which is preventing him from running full speed. It's being called a deep bruise.
"I still haven't been able to run," he said.
Right-hander David Phelps is out for the rest of the year with a stress fracture of the radius bone in his right forearm.
"It doesn't seem like anything that will extend into next year," Phelps said.