Lance Stephenson is clearly emotional about his old pal Sebastian Telfair getting sentenced to 3.5 years in prison ... telling TMZ Sports, "That's like family right there."
Telfair -- a 1st round pick in the 2004 NBA Draft -- was found guilty of felony weapons possession stemming from a crazy 2017 arrest where cops say they found an arsenal of weapons, ammo, bulletproof vest and weed. He's currently serving out his sentence in a NY State Prison.
28-year-old Stephenson tells us he grew up playing ball and training with 34-year-old Telfair .