Troubled NFL QB Trevone Boykin has been charged with felony aggravated assault for allegedly punching his GF and cracking her jaw back in March ... and now he's facing 20 YEARS in prison.
TMZ Sports has learned ... Boykin was indicted for 2nd degree felony aggravated assault-serious bodily injury by a grand jury in Tarrant County, TX on Friday.
At the time of the incident, Boykin's longtime GF, Shabrika Bailey, claims he choked her and broke her jaw during a physical fight before finally taking her to the hospital for treatment.
As for Boykin, he's vehemently denied any physical altercation took place.
Boykin was a stud at TCU but had issues off the field -- including a fist fight with cops days before the Alamo Bowl.
He was undrafted -- but later signed a contract with the Seattle Seahawks and seemed to be doing well until the domestic violence arrest.
The Seahawks cut him back in March -- the same day he was arrested.