Floyd Mayweather is ready to go out in public again ... sitting courtside at the Miami Heat game on Wednesday -- the first time we've seen him since the shooting in Atlanta.
As we previously reported, Mayweather's longtime bodyguard, Greg La Rosa, was shot during an ambush on Floyd's 3-vehicle entourage early Monday morning. Cops believe the entourage was specifically targeted.
Cops are still trying to figure out why someone would want to kill Floyd or someone on his team -- but in the meantime, Mayweather picked up and went to Miami.
He didn't look scared ... Floyd was still rockin' his insanely expensive jewelry and was smiling -- but ya gotta think he's still concerned because cops have no arrests and have not named a suspect.