Glen "Big Baby" Davis has been formally charged with felony assault stemming from an alleged violent altercation in April and if he's convicted ... he faces up to 7 YEARS in prison, TMZ Sports has learned. 

We broke the story ... the 32-year-old ex-NBA player was arrested last month after prosecutors say he beat the living hell out of a man outside a West Hollywood nightclub. 

The alleged victim was hospitalized with several major injuries including facial fractures, a broken tooth and broken ribs. 

A rep for the L.A. County District Attorney's office tells us the official charge is felony assault with force likely to cause great bodily injury ... and it carries a possible 7-year prison sentence. 

We've reached out to Davis multiple times over the past few months -- but he's gone radio silent.