Shawne Merriman Launches MMA Promotion, Considering Fighting

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 ... he's been around the combat sports game for years -- and was even scheduled to take a bare-knuckle fight in late 2018 before things fell apart.

Merriman isn't the 1st famous former athlete to launch an MMA promotion ... Oscar De La Hoya started Golden Boy MMA last year and put on Chuck Liddell-Tito Ortiz III.

Lights Out Xtreme Fighting's 1st card is going down May 11 in Burbank.