I am guessing that Barbelo is going to tell me this was modern restored and the adjoining paver...
In the image below, your image is in the red circle. It may be a remnant of a pillar.
In the blue circle is the in situ pillar. But it has been partially restored by gluing a broken top on to it and letting the glue run down the side.
What do you think happened with the block in the yellow circle?