Copyright TMZ

Tony Allen -- a former star and lockdown defender for the Memphis Grizzlies -- is locked up behind bars in Arkansas on drug charges ... TMZ has learned. The Poinsett County Sheriff's Office tells TMZ ... Allen is facing two charges of drug possession -- one felony and one misdemeanor -- and he's currently being held without bond. According to the AP ... Allen was riding as a passenger in a vehicle that was pulled over on an interstate about 50 miles from Memphis. Authorities say Allen was found with a bag of marijuana on him ... and when deputies searched the vehicle, they allegedly found cocaine in a cigarette box. Allen later posed for a mug shot in a white T-shirt ... and based on his expression, he's not thrilled about it. The 43-year-old was a staple on the Grizzlies from 2011 to 2017, and also played for the Boston Celtics and New Orleans Pelicans. His jersey was retired by the Grizzlies in March -- and he's widely considered one of the best defensive players of all time. This isn't the first time Allen's been in trouble with the law ... in 2023, he pled guilty in a federal case involving an NBA health insurance and fraud scheme -- and was sentenced to community service and three years of supervised probation.