Lamar Odom is getting professional help — TMZ Sports is told the NBA champion checked into rehab after his recent DUI arrest.

Odom entered a 30-day treatment program at the iRely Recovery facility in Los Angeles … after his run-in with police sparked some triggers from his past that he wanted to address.

The former Lakers star is looking to shake marijuana  … as he was afraid his smoking could lead to doing hard drugs again, his manager, Gina Rodriguez, told us.

While he previously said alcohol and narcotics did NOT play a role in his arrest, Odom isn’t taking any chances … which makes sense after what he went through in 2015, when he almost died from an overdose.

LO hasn’t gotten treatment in years, but we’re told the champ is optimistic on his comeback … and the goal is to be “clean and clear” once again.

As we previously reported, cops said Odom’s car reeked of weed after he was pulled over for speeding. Officers said he later owned up to smoking earlier in the day.

During the stop, Odom even referenced the night he nearly died … saying while he never suffered a traumatic brain injury, he did suffer “12 strokes and six heart attacks and that he was poisoned at a brothel in Pahrump.”