The home run also was Stanton's first in a game since June 24. Two days later, the three-time All-Star broke the hamate bone in his left hand and missed the rest of the season.
The blast occurred during a televised game, as Miami starter Tom Koehler was being interviewed.
When the ball was hit, Koehler gave the call: "Big fella goes boom!"
The words echoed in the Marlins' clubhouse and dugout. With Stanton, it's always a matter of time before he connects. And if his history holds true, once he gets one, more usually follow.
"It's good any time," manager Don Mattingly said. "To hit one is always a good feeling. I'm sure it helps him. You always want to get one before you leave here."
Not that anyone was reading too much into Stanton's power numbers, especially since he has just 17 Grapefruit League at-bats. The blast, though, may be a sign the slugger is getting more comfortable.
"It's good to get on top of a fastball," Stanton said. "The past couple, I seem to pop up."
Stanton's laser came off a 98-mph fastball on a 3-0 count.
I'm glad I had some [fastball] velocity today, to test it," Stanton said.
Earlier in Spring Training, Stanton missed a week due to a sore right knee.
Missing so much time has delayed Stanton's timing and general feeling at the plate. He entered the day with one RBI before connecting off the Cardinals' closer.
Just seven days away from leaving their Spring Training, the Marlins are hopeful their slugger will start heating up.
"You'll definitely see more of him and everyone else," Mattingly said. "We'll try to keep him off the long trip [Saturday to Kissimmee, Fla., to face Houston]. We'll do a little manipulation as we get closer with him, and get him a lot of at-bats towards the end."
Stanton isn't worried about the results right now. In the final week of camp, he merely is seeking hard contact.
"Not homers," he said. "Just hitting fastballs hard. I don't care if they're outs or whatever."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter @JoeFrisaro and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.