2:24 PM PT -- TMZ Sports has obtained a statement from Chambers ... who says his comment was, "hurtful, insensitive and unacceptable."
"I cannot apologize enough for what I said, and I will carry that forever."
Chambers continues ... "I try and respond to mistakes I have made by learning and growing, and I hold myself accountable and strive to be a better person and a better coach. In talking with our players and their families."
"I am committed to seeking knowledge and gaining a better understanding of diverse perspectives and impact of bias in our society. I have much more to learn."
Ex-Penn State basketball player Rasir Bolton says he left the program due to racially insensitive comments made by head coach Pat Chambers ... including a reference to a "noose" around his neck.
Chambers is how apologizing -- saying it was never his intention to offend.
20-year-old Bolton says the incident went down in January 2019 ... days after Chambers was suspended 1 game for pushing another player during a timeout.
"A 'noose' around my neck is why I left Penn State," Bolton -- who transferred to Iowa State after his freshman season -- said in a statement on Twitter.
"Due to other interactions with Coach, I knew this was no slip of the tongue."
According to ESPN, Bolton claims Chambers' whole comment went as follows:
"I want to be a stress reliever for you. You can talk to me about anything. I need to get some of this pressure off you. I want to loosen the noose that’s around your neck."
Bolton says he reported the incident to his academic advisor and the athletic department ... only to hear back from the school 6 months later, after he decided to leave the program.
Chambers has owned up to the comment ... and has since apologized.
"I didn’t realize that word would hurt him, and I am truly, truly sorry for that," Chambers told ESPN.
Bolton says he went public to bring awareness to what players have to deal with ... and he wants change.
"I wasn't the first and I know I wasn't the last. Everyone's position to speak out isn't the same, so I am only speaking for myself. There is a serious need for change in the way players are protected and helped across the country when faced with these situations."
"Surface level resources are not good enough. In most cases, it is the Coach who is protected, while the player is left to deal with it or leave."