Stanton was held out of the starting lineup for Wednesday's game against Atlanta. The young outfielder was in a 1-for-14 slump with seven strikeouts, and manager Edwin Rodriguez decided to give him a brief break.
"Sometimes he looks like Willie Mays out there," Rodriguez said. "Other times you wonder."
Stanton pinch-hit in the seventh and struck out with the bases loaded. He singled home two runs with two outs in the ninth, but the Marlins lost 3-2 in 10 innings.
Since breaking into the majors a year ago at age 20, Stanton has won raves for his power while totaling 35 home runs and 94 RBIs.
This season he had 13 homers through Tuesday, but he also had 58 strikeouts in 193 at-bats while hitting .254. With runners in scoring position he was batting .222.
"He's learning to be a hitter," Rodriguez said. "He has outstanding numbers for any major leaguer, but he has also been very inconsistent. We were aware of the growing pains he would have to go through, and mentally he's taking it fine."
Stanton is hardly the only slumping hitter for the Marlins. They have lost seven consecutive games, including six at home, and are batting .148 during their homestand with runners in scoring position.
Stanton started the year batting cleanup but has hit only .182 in that spot. Fifteen games into the season, he was batting only .194.
But despite his rough patches, he ranks sixth in the NL with a slugging percentage of .544, and ninth with an on-base-plus-slugging percentage of .888.
Dan Uggla, a teammate last season before being traded to the Braves, ranks Stanton's raw power No. 1 in baseball.
"Anybody who watches Stanton take bp -- nobody can touch him," Uggla said. "It still baffles me to watch him hit and see the distance he puts on balls. He's in a class by himself."