Jacksonville's new receiver wrote a piece for The Players Tribune on Wednesday ... titled "A Letter to the Game."

"I f***ed up," the 28-year-old said. "I’m not here to sugarcoat anything. In 2021, I made the worst mistake of my life by gambling on football."

Remember, CR was suspended indefinitely for wagering on NFL games -- a huge no-no -- and ultimately missed all of last season.

Ridley says the bets started when he stepped away from the Atlanta Falcons to focus on his mental health. He was battling depression and anxiety, which he says started when he suffered a foot injury. He says his wife was also dealing with trauma from their house being burglarized. So, it was a difficult time for his family.

"I was looking for anything to take my mind off of things and make the day go by faster," Ridley wrote. "One day, I saw a TV commercial for a betting app, and for whatever reason, I downloaded it on my phone."

He says he deposited $1,500 and started placing bets on NBA games, as well as the Falcons, which he says was just his way of rooting for his team.

"I didn’t have any inside information. I wasn’t even talking to anybody on the team at the time. I was totally off the grid," Ridley said adamantly.

Of course, the NFL ultimately found out and threw the book at Calvin ... a moment he calls "probably the worst day of my life." The trash-talking and trolling didn't help either.

"I paid the price, believe me. I’ve seen all the jokes. I’ve seen all the hate," Ridley said.

"All I want is for people to understand that, when I made those bets, there was a hell of a lot more going on with me."

But, now the Florida native -- who was reinstated on Monday -- is ready to turn up with his new team in Jacksonville, and he feels stronger than ever, mentally and physically.

"It feels so good to be back home in Florida, where this dream started, with a clean slate," Ridley said.