NFL's Trevone Boykin -- Charged with Assault ... For Alamo Bowl Bar Fight

Ex-TCU quarterback Trevone Boykin has been charged with assault for allegedly striking a police officer after he was thrown out of a bar days before the Alamo Bowl ... TMZ Sports has learned.

Boykin -- who has since signed with the Seattle Seahawks -- was captured on video being physically removed from Pat O'Briens bar in San Antonio on Dec. 31st ... while throwing punches at staff on the way out.

Once he was in the street, Boykin can be seen rushing toward bike cops who rolled up to the scene. Officials say he struck one of the officers while they tried to take him into custody.

Boykin was initially booked for assaulting a public servant (a 3rd degree felony), public intoxication and resisting arrest.

But it appears he caught a huge break -- 'cause according to court docs obtained by TMZ Sports, the 22-year-old was only officially charged with one count of misdemeanor assault with bodily injury.

If convicted, Boykin faces up to 1 year in jail.

Court docs say ... multiple officers witnessed the alleged assault. The witnesses say they saw multiple cuts and scrapes on the victim.