Over 2 seasons, Fultz -- who's now on the Orlando Magic -- has only played in 33 games (he started 15) ... averaging only 7.7 points per game, 3.4 assists and 3.4 rebounds.
But, Markelle -- who's still a ridiculously young 21-year-old with supreme talent -- is trying to turn the bust ship around ... and he's looking to Kobe for help.
Fultz spent a good chunk of the summer at MAMBA Sports Academy in Southern California ... working daily with the academy's trainers.
We're told Markelle even had a sit-down with Kobe ... where Bryant schooled Fultz on the "Mamba Mentality" -- which in KB's words means to "constantly try to be the best version of yourself."
Will Kobe's greatness rub off on Fultz? Stay tuned. NBA season kicks off next month.