46-year-old Callaway -- who most recently served as the Los Angeles Angels pitching coach -- has been under league investigation since 5 women came forward in February and alleged several instances of misconduct ... including sending unsolicited shirtless selfies and asking for nude photographs, among other claims.

MLB concluded its investigation and determined Callaway violated league policies. The league says placing Callaway on the Ineligible List is "warranted" through the completion of the 2022 season, when he will be eligible for reinstatement.

Callaway spoke about the punishment in a statement to ESPN minutes ago ... saying, "My family and I fully support MLB’s strong stance against harassment and discrimination and are grateful to the Commissioner and his office for their thorough investigation."

"I apologize to the women who shared with investigators any interaction that made them feel uncomfortable. To be clear, I never intended to make anyone feel this way and didn’t understand that these interactions might do that or violate MLB policies."

"However, those are my own blind spots, and I take responsibility for the consequences."

He added ... "In my 25 years in professional baseball, I have never taken for granted the privilege of being even a small part of this great game of ours."

"To say I regret my past poor choices would be an understatement. I remain hopeful that I can return to baseball when eligible at the conclusion of next season, but for now, I plan to work on my own shortcomings and repairing any damage I have caused with my colleagues and, particularly, my family."