My tub drain doesn't have its' stopper anymore. There's still a post in there that is connected to the crossbar of the drain. The post twists around easily but doesn't come out. I want to take out the protruding post so I can just buy a plastic stopper to stop up the tub. I'm not sure what kind of stopper came with the tub. But all that's left is the post and I'm not sure if it's stuck or if it's actually connected to the crossbar. Is there anything to do about this post beside replace the whole drain?

Is there a screw anywhere in the middle?

Is it a threaded post? Can you post a picture? Could be a Twist-and-close like this Westbrass 1-1/2 in. NPSM Coarse Thread Twist-and-Close Bath Drain Plug-79438CP-Z - The Home Depot or even a pop up.