Lamar Odom -- I CHOSE Not to Attend Kim Kardashian/Kanye West Proposal

Lamar Odom tells TMZ he hasn't been blackballed from the Kardashian family -- and WAS invited to Kanye's big proposal to Kim -- but he CHOSE not to go because he had better things to do that night.

It was just one of the topics Lamar addressed on his way out of the Spitting Chicken Cantina in Sherman Oaks, CA last night ... telling us about his friendship with Kobe, his relationship with his dad and his battle to get back into the NBA.

In fact, L.O. says he believes he's back in playing shape -- telling us, "I can play a basketball game and probably play really well."

He wanted to prove it by showing off his physique -- jokingly asking, "Do you wanna see me with my shirt off or my pants down?"

Don't worry, he didn't follow through on his offer.