Shawne Merriman isn't locked into a WWE deal just yet ... TMZ Sports has learned the former NFL star is still hammering out a contract -- but it's not just for his announcing skills.

Merriman made his WWE debut during the WrestleMania 30 pre-show as an analyst -- and he was pretty damn impressive -- so now the two sides are working towards finalizing an agreement.

We're told announcing isn't the sole reason for his contract though.  

Merriman will also train at the WWE's Performance Center in Florida ... and depending on his progress, Shawne could get a chance to wrestle other developmental talent on their WWE Network show NXT.

Whatcha gonna do, brother?  When "Lights Out" runs wild on you!!!!