Rob Gronkowski says he's not closing the door on his NFL career -- saying he's open to strap on the pads again if he starts jonesing for some football action!
Gronk says his body is finally "pain free" after getting into bed with a CBD company called CBD Medic ... and he hosted a media event on Tuesday to announce his partnership.
In short, Gronk says CBD has helped him get right since retiring and he hopes the league and other star players like Tom Brady will help get CBD approved for pain management in the NFL.