Adam Silver is vouching for Toronto Raptors President Masai Ujiri -- saying the guy is a good dude ... but the NBA commish tells TMZ Sports he's still investigating Ujiri like he would anyone else.
Of course, Ujiri is facing some stiff allegations after shoving a cop after Game 6 of the NBA Finals ... with the officer's attorney saying his client suffered a concussion and a jaw injury in the altercation.
ALTERNATE FAN ANGLE: You can see Masai Ujiri apparently yelling back and forth with the Police Depty he had an alleged incident with.