CC Sabathia -- I Knew I Was an Alcoholic In '12 ... Secret Hotel Binges

NY Yankees star CC Sabathia says he desperately tried to cover up his alcoholism for years -- boozing hard in secret hotel binges -- until finally realizing he needed to address the problem.

"In 2012, I kind of came to the realization I was an alcoholic," Sabathia said on ABC's "Good Morning America" ... "and I was kind of battling it without any help."

"I would go a couple, you know, two, three months at a time sober, and then I would just relapse, and, you know, go on these weekends when I thought nobody was paying attention, and I would get in a hotel room and drink out of the minibar, pretty much everything."

Sabathia says he feels relief now that everyone knows about his issue -- "I can just, you know, start the healing process and take steps forward to get myself better."

The 35-year-old recently completed a stint in rehab -- and says he's proud of the support he's received from Yankees stars like Derek Jeter and Alex Rodriguez ... as well as stars from other teams.

"Torii Hunter, Dave ... 'Big Papi's' been calling me a lot. And, you know, I got to thank those guys. I'm truly blessed to be able to have friends like that."