Matt Barnes: NBA Investigating 'Chasing' Incident

The NBA has launched an investigation in the Matt Barnes vs. John Henson "chasing" incident -- though we're told there was NO FIGHT ... league sources tell TMZ Sports.

Barnes jogged into the locker room after he and Henson were ejected from Thursday night's Bucks vs. Grizzlies game ... with some reports saying Barnes "chased" after Henson looking to throw down.

But our sources are adamant ... nothing happened after the game, period -- with each player going to his respective locker room and that was it.