Lamar Odom -- I'm Sober, And I Can Kick Drugs WITHOUT REHAB

Lamar Odom says he's been sober for 5 days ... and he believes he can maintain sobriety WITHOUT going to rehab.

Sources connected to the troubled BBaller tell TMZ ... Lamar believes in what he calls "self-healing" and says he has the willpower to kick his drug habit on his own.

Lamar says he's done it successfully before and is convinced he can do it again.

Toward that end, he is telling people he is removing certain "friends" from his life ... so he doesn't relapse.

Lamar says he's open to getting professional help, but only in private and not in a rehab facility. He has not yet committed to getting such help.

Lamar is very mindful of the fact that training camp has just started. Although he wants to save his marriage to Khloe Kardashian, our sources say his motivation for sobriety seems to be more focused on his basketball career. Lamar believes once he's achieved a level of sobriety, he can re-join a team.

TMZ broke the story ... Lamar had a devastating crack problem in addition to an addiction to other drugs, including cocaine. He was in rehab for 3 weeks a little more than a year ago before bailing.