The bottom section of this relief, like others on the Sebasteion, is left in a roughed-out condition. Once inserted into the monument this section of the panel would not have been visible from the ground.
Notes
Like all of the panels used in the Sebasteion this one is carved from a single piece of stone, which means the carving could have been completed before it was inserted into the structure, though there is no proof that this was necessarily the case.