Lakers co-owner Jesse Buss doesn't have to go too far to check in on his star player ... 'cause dude just bought a mansion right up the street from LeBron James!!
Jesse -- the youngest of the 6 Buss siblings -- ponied up $10 MILLION for a pad in Brentwood just feet from LBJ's palace ... and the place is sick.
It's 6,500 square feet, has 3 stories, 6 bedrooms, 8 bathrooms, a home theater, a yoga room ... AND an infinity pool.
Ari Shram and Jen Beron of The Agency -- a high-end real estate firm -- helped Jesse land the spot .