The NBA is admitting it's forcing LaMelo Ball to cover up his new neck tattoo ... claiming the Charlotte Hornets star's ink is violating league policy.
The 22-year-old got the "LF" put just below his left ear back in September ... to represent his middle name as well as his LaFrancé clothing line.
But, recently, he's covered it up with a bandage ... and on Friday, NBA spokesman Tim Frank said in a statement to ESPN it's because "players are prohibited from displaying commercial logos or corporate insignia on their body or in their hair during games.