If it was me, I would inspect closely and place in tank, however not exactly 100% safe, phestilla nudis can be a cocern but only eat porites, my guess is you may not have much if any porites in your tank, if the worms were burrowed in a type of encrusting montipora and you were adding them to the typical sps aquarium with quite a bit of montipora it would be a different story. If you have an QT with the proper lighting/flow already setup it can't hurt but I'd feel comfortable just adding to the tank.
Just my .02.