CHICAGO -- One day after announcing he was stepping away from baseball, Yermin Mercedes was back with the Chicago White Sox's Triple-A affiliate.

The White Sox confirmed Thursday that Mercedes, the surprising rookie who carried the team with his booming bat early in the season and got sent to the minors following a prolonged slump, was in uniform for the Charlotte Knights' game against the Durham Bulls.

Mercedes also apologized Thursday in an Instagram post.

"I'm never going to give up," he wrote. "I spent 10 years in the minor league and I have always understood that this is a big and long process but the talent that I have shown speaks for itself. With the greatest humility and speaking from the heart ... my dream is to be an established player in the major leagues. I asked God to give me that opportunity and I've got it 3 months ago. I owe myself to my family, my organization and my fans. I asked again for forgiveness if I have failed them.

"Baseball is in my blood ... and I thank God for guiding me to the right path and to make the correct decision. To those going to a similar situation, forget the criticisms and bad comments. They will always exist to trample on your personality. God bless y'all.

"I love everyone. I'm back."

It was a turnaround from his since deleted post Wednesday night that included an image with the words "it's over." He wrote in the caption, "I'm stepping aside from baseball indefinitely..! God bless you. It's over."

Hall of Fame manager Tony La Russa vowed following Wednesday's loss to Minnesota to reach out to Mercedes and insisted the player has a "big league future."

"I understand you're at Triple-A, you've tasted the big leagues, you can get emotional," La Russa said. "But I don't know more than that."

Mercedes, 28, sparked Chicago's offense through the opening months of the season, batting .415 with five homers and 16 RBIs in 22 games in April. In May, Mercedes angered La Russa by homering on a 3-0 pitch in the ninth inning of a game the White Sox led 15-4.

Mercedes eventually cooled off, hitting .150 (16 for 107) over his final 31 games with Chicago before being demoted to Charlotte on July 2.

The Associated Press contributed to this report.