Ex-NFL star Shawne Merriman is jumping from the gridiron to the cage -- launching an MMA promotion -- and he's considering fighting ... TMZ Sports has learned.
We talked to Shawne -- a 6'4", 265 lb. linebacker who made 3 Pro Bowls in his 8-year career -- about the creation of his new promotion, Lights Out Xtreme Fighting.
Unlike Dana White, Merriman tells us -- if the opponent was right -- he'd be down to fight ... despite co-owning the biz.
The former Chargers star isn't new to mixed martial arts .