Tommy Rowan of the Philadelphia Inquirer reported the news, noting Kendricks faces up to 25 years in prison after his plea. He has a sentencing hearing scheduled for December.
"Because I know I was wrong," Kendricks told United States district judge Gene E.K. Pratter when asked why he was pleading guilty. "I know that I made the decision to accept information, secret information, and it wasn't the right thing to do."
United States attorney Bill McSwain announced on Aug. 29 that Kendricks was being charged with insider training.
Kendricks issued a statement in response to the charges, admitting he got involved in the situation with a friend four years ago:
"Four years ago, I participated in insider trading, and I deeply regret it. I invested money with a former friend of mine who I thought I could trust and who I greatly admired. His background as a Harvard graduate and an employee of Goldman Sachs gave me a false sense of confidence.
"To this point, I had worked my tail off since I was five years old to become a football player. I was drawn in by the allure of being more than just a football player. While I didn't fully understand all of the details of the illegal trades, I knew it was wrong, and I wholeheartedly regret my actions."
The Cleveland Browns, who signed Kendricks in June, released him the same day he was charged.
A six-year NFL veteran, Kendricks played with the Philadelphia Eagles from 2012 through 2017. He won a Super Bowl with the team last season.