Ex-NBA Player John Wallace -- Arrested In Brooklyn ... Dude, You Can't Drive

Ex-NBA player John Wallace -- a 1st round pick in the '96 draft -- was arrested in Brooklyn on Thursday in a routine traffic stop gone bad ... TMZ Sports has learned.

Law enforcement tells us ... Wallace's 2010 Yukon Denali was pulled over around 10:15 AM for failing to use his blinker -- and during the stop, cops noticed his license had been suspended. We don't know why his license had been suspended.

The 42-year-old was taken into custody and booked for "aggravated unlicensed operator" -- a charge that carries a maximum 30 days in jail if convicted.